Dont give up on love Essay Example for Free

Dont give up on love Essay Shilpa’s heart was broken by the Khiladi of Bollywood, Akshay Kumar but she never gave up on love. The rumour mills were abuzz about her ‘relationship’ with director Anubhav Sinha, but she firmly denied them. After winning Big Brother, Shilpa went to launch her signature perfume S2 and met Raj occasionally for the launch preparations. On their first media appearance, Shilpa called Raj, her ‘business friend’ but their frequent meetings soon took a personal turn. Shilpa soon announced her engagement to the world and proudly showed off the 20 carat diamond ring which had been gifted to her by Raj. A firm believer of karma and past life, Shilpa went on to say in an interview that Raj was a part of her past life and now they are back together. Lesson Learnt: So girls, no matter how many boys break your heart; don’t ever settle for anyone except for your Mr. Right. Never embarrass your ex publicly You may be seething in anger and may want to kill your ex for two timing you, but in public, you must always be at your dignified best. Even though Shilpa was heartbroken after her break up, she has often said in interviews that there is no animosity between her and Akshay and they are good friends. Akshay and Shilpa have come face to face on a number of occasions, most recently on the celebrity dance show Nach Baliye, but Shilpa has always been pleasant to her ex-flame. Lesson Learnt: Your ex may be the devil’s incarnate, but you should never wash the dirty linen in public. Maintain dignity under pressure Life wasn’t easy for this gorgeous actress, but things took a turn for worse when she entered the celebrity Big Brother 5 in 2007. Racial slurs by her fellow contestants Jade Goody, Danielle Lloyd, Jack Tweed and Jo OMeara rattled her but she did not give up. She stayed in the house and soon emerged as Britain’s favourite with 63 per cent votes. Not the one to hold grudges, Shilpa soon forgave Jade Goody and other contestants. She told the host of the show Davina McCall, â€Å"People make mistakes and were all human beings, were all fallible. Lesson Learnt: In a high pressure situation, never let your attackers get to you. Keep yourself in positive spirits, maintain your dignity and always let bygones be bygones. Make time for family You may be swiftly climbing the success ladder, but don’t forget your family in all that excitement. Shilpa decided to take a break from her acting carrer for a year after her son Viaan was born. She signed up for a couple of endorsements, but ensured that her schedule would not take up too much of her time. 1. Dont give up on love Shilpa’s heart was broken by the Khiladi of Bollywood, Akshay Kumar but she never gave up on love. The rumour mills were abuzz about her ‘relationship’ with director Anubhav Sinha, but she firmly denied them. After winning Big Brother, Shilpa went to launch her signature perfume S2 and met Raj occasionally for the launch preparations. On their first media appearance, Shilpa called Raj, her ‘business friend’ but their frequent meetings soon took a personal turn.less 2. Shilpa soon announced her engagement to the world and proudly showed off the 20 carat diamond ring which had been gifted to her by Raj. A firm believer of karma and past life, Shilpa went on to say in an interview that Raj was a part of her past life and now they are back together. Lesson Learnt: So girls, no matter how many boys break your heart; don’t ever settle for anyone except for your Mr. Right. 3. Never embarrass your ex publicly You may be seething in anger and may want to kill your ex for two timing you, but in public, you must always be at your dignified best. Even though Shilpa was heartbroken after her break up, she has often said in interviews that there is no animosity between her and Akshay and they are good friends. Akshay and Shilpa have come face to face on a number of occasions, most recently on the celebrity dance show Nach Baliye, but Shilpa has always been pleasant to her ex-flame. Lesson Learnt: Your ex may be the devil’s incarnate, but you should never wash the dirty linen in public.less 4. Maintain dignity under pressure Life wasn’t easy for this gorgeous actress, but things took a turn for worse when she entered the celebrity Big Brother 5 in 2007. Racial slurs by her fellow contestants Jade Goody, Danielle Lloyd, Jack Tweed and Jo OMeara rattled her but she did not give up. She stayed in the house and soon emerged as Britain’s favourite with 63 per cent votes. 5. Not the one to hold grudges, Shilpa soon forgave Jade Goody and other contestants. She told the host of the show Davina McCall, â€Å"People make mistakes and were all human beings, were all fallible. Lesson Learnt: In a high pressure situation, never let your attackers get to you. Keep yourself in positive spirits, maintain your dignity and always let bygones be bygones. 6. Make time for family You may be swiftly climbing the success ladder, but don’t forget your family in all that excitement. Shilpa decided to take a break from her acting carrer for a year after her son Viaan was born. She signed up for a couple of endorsements, but ensured that her schedule would not take up too much of her time. 7. In an industry where actresses are always under the media scanner for their weight-issues, Shilpa says that she is no hurry to lose post-pregnancy flab. She believes â€Å"As we are in the glamour business, we are always scrutinised for our appearances and are bound to have insecurities. But for a mother, these first four months are very crucial for the childs health. You should not compromise with it.† 1. Dont give up on love Shilpa’s heart was broken by the Khiladi of Bollywood, Akshay Kumar but she never gave up on love. The rumour mills were abuzz about her ‘relationship’ with director Anubhav Sinha, but she firmly denied them. After winning Big Brother, Shilpa went to launch her signature perfume S2 and met Raj occasionally for the launch preparations. On their first media appearance, Shilpa called Raj, her ‘business friend’ but their frequent meetings soon took a personal turn.less 2. Shilpa soon announced her engagement to the world and proudly showed off the 20 carat diamond ring which had been gifted to her by Raj. A firm believer of karma and past life, Shilpa went on to say in an interview that Raj was a part of her past life and now they are back together. Lesson Learnt: So girls, no matter how many boys break your heart; don’t ever settle for anyone except for your Mr. Right. 3. Never embarrass your ex publicly You may be seething in anger and may want to kill your ex for two timing you, but in public, you must always be at your dignified best. Even though Shilpa was heartbroken after her break up, she has often said in interviews that there is no animosity between her and Akshay and they are good friends. Akshay and Shilpa have come face to face on a number of occasions, most recently on the celebrity dance show Nach Baliye, but Shilpa has always been pleasant to her ex-flame. Lesson Learnt: Your ex may be the devil’s incarnate, but you should never wash the dirty linen in public.less 4. Maintain dignity under pressure Life wasn’t easy for this gorgeous actress, but things took a turn for worse when she entered the celebrity Big Brother 5 in 2007. Racial slurs by her fellow contestants Jade Goody, Danielle Lloyd, Jack Tweed and Jo OMeara rattled her but she did not give up. She stayed in the house and soon emerged as Britain’s favourite with 63 per cent votes. 5. Not the one to hold grudges, Shilpa soon forgave Jade Goody and other contestants. She told the host of the show Davina McCall, â€Å"People make mistakes and were all human beings, were all fallible. Lesson Learnt: In a high pressure situation, never let your attackers get to you. Keep yourself in positive spirits, maintain your dignity and always let bygones be bygones. 6. Make time for family You may be swiftly climbing the success ladder, but don’t forget your family in all that excitement. Shilpa decided to take a break from her acting carrer for a year after her son Viaan was born. She signed up for a couple of endorsements, but ensured that her schedule would not take up too much of her time. 7. In an industry where actresses are always under the media scanner for their weight-issues, Shilpa says that she is no hurry to lose post-pregnancy flab. She believes â€Å"As we are in the glamour business, we are always scrutinised for our appearances and are bound to have insecurities. But for a mother, these first four months are very crucial for the childs health. You should not compromise with it.† 8. In another interview when she was asked what things she would grab in case there is a fire in her home, the gorgeous actress replied, â€Å"I would just make sure that my family escapes. Material things dont matter.† Lesson Learnt: Family comes first, always! And Ladies, enjoy each and every phase of your life. Motherhood is a blessing and do not let any nasty comments about your weight or appearance affect you.

Genotoxicity of Endodontic Irrigants and Medicaments

Genotoxicity of Endodontic Irrigants and Medicaments Abstract Genotoxicity describes a deleterious action on a cells genetic material affecting its integrity. This includes both certain chemical compounds and certain types of radiation. Genotoxic substances are all those with affinity to interact with DNA which is not proof of their dangerousness to humans, but does render them potentially mutagenic or carcinogenic. This review will address the genotoxicity of endodontic irrigants, medicaments, and sealers. It has been postulated that exposure of living tissues to cytotoxic agents can result in chronic cell injury, compensatory cell proliferation, hyperplasia, irritation, degeneration or tissue necrosis (1) and ultimately tumor development (2, 3). It is likely that proliferation may increase the risk of mutations within target cells and also be important in selective clonal expansion of exogenously or endogenously initiated cells from pre-neoplastic foci and eventually tumors (2). Thus, the DNA damage may diminish the self-repairing potential of tissue (4). In light of these considerations, genotoxicity and cytotoxicity assays gained widespread acceptance as an important and useful indicator of carcinogenicity. Definition of genotoxicity In genetics, genotoxicity describes a deleterious action on a cells genetic material affecting its integrity. This includes both certain chemical compounds and certain types of radiation. Genotoxic substances are all those with affinity to interact with DNA which is not proof of their dangerousness to humans, but does render them potentially mutagenic or carcinogenic (5). Genotoxicity of root canal irrigants Sodium hypochlorite Sodium hypochlorite (NaOCl) is recommended as the main endodontic irrigant because of its ability to dissolve organic matter together with its broad antimicrobial action (6). NaOCl is commercially available as aqueous solutions with concentrations ranging from 1% to 15% and having an alkaline pH with values around 11 (7). Sodium hypochlorite has a wide range activity against both Gram positive and Gram negative bacteria. It is the strongest antifungal agent among root canal irrigations and medications. Furthermore, it is the only root canal irrigant that can destroy the microbial biofilm effectively (6, 7). Hamaguchi and Tsyutsui (8) showed that NaOCl was not genotoxic to mamalian cells. Hagiwara et al. (9) showed that sodium hypochlorite induced chromosome aberrations in Syrian hamster embryo (SHE) cells when treated in the presence of exogenous metabolic activation. Aubut et al. (10) revealed that neutralizing a 2.5% NaOCl solution did not induce any genotoxic effect. Marins et al. (11) showed that NaOCl did not induce any genotoxic effect. Chlorhexidine CHX is a synthetic cationic bis-guanide that consists of two symmetric 4-cholorophenyl rings and two biguanide groups connected by a central hexamethylene chain. CHX is a positively charged hydrophobic and lipophilic molecule that interacts with phospholipids and lipopolysaccharides on the cell membrane of bacteria and then enters the cell through some type of active or passive transport mechanism (12). Its efficacy is due to the interaction of the positive charge of the molecule and the negatively charged phosphate groups on microbial cell walls (12), thereby altering the cells osmotic equilibrium. This increases the permeability of the cell wall, which allows the CHX molecule to penetrate into the bacteria. CHX is a base and is stable as a salt. The most common oral preparation, chlorhexidine gluconate, is water-soluble and at physiologic pH, it readily dissociates and releases the positively charged chlorhexidine component (12). At 0.2% concentration, due to the leakage of low mol ecular weight substances(potassium and phosphorous) from the bacterial cell wall, CHX is bacteriostatic. On the other hand, at 2% concentration, CHX is bactericidal, as precipitation of the cytoplasmic contents occurs and resulting in cell death (13). Ribeiro et al. (14) revealed that chlorhexidine digluconate is able to induce primary DNA damage in leukocytes and in oral mucosal cells, but no chromosome breakage or loss in erythrocytes. Another study indicated that CHX in 0.01% and 1% concentrations did not induce DNA damage. Yeung et al. (15) stated that potential genotoxicity and tissue damage when extruded into the periradicular tissue and at higher concentrations should be considered during periodontal and endodontic practice. Li et al. (16) revealed that CHX-induced genotoxicity on macrophages may be via reactive oxygen species generation. MTAD BioPure (Dentsply, Tulsa Dental, Tulsa, OK, USA), otherwise known as MTAD, was introduced by Torabinejad et al. in 2003 (17). It is composed of 3% doxycycline, 4.25% citric acid and a detergent (0.5% Polysorbate 80) (17). Marins et al. (18) assessed the genotoxicity of MTAD using single cell gel (comet) assay. Results showed that the BioPure MTAD was able to promote DNA breakage in CHO cells only at the highest concentration tested as well as to induce significant increase in tail moment at all tested concentrations in murine fibroblasts. Another study revealed that MTAD did not cause cell death, but presented genotoxic effects (19). EDTA EDTA (Ethylenediaminetetraacetic acid) refers to the chelating agent with the formula (HO2CCH2)2NCH2CH2N(CH2CO2H)2. This amino acid is widely used to sequester di- and tri-valent metal ions. EDTA binds to metals via four carboxylate and two amine groups. EDTA forms specially strong complexes with Mn(II), Cu(II), Fe(III), and Co(III). EDTA is mostly synthesised from 1,2-diaminoethane (ethylenediamine), formaldehyde (methanal), water and sodium cyanide. This yields the tetra sodium salt, which can be converted into the acidic forms by acidification (20, 21). EDTA is a polyamino carboxylic acid and a colourless, water-soluble solid. It is widely used to dissolve limescale. Its usefulness arises due to its role as a hexadentate ligand and chelating agent, i.e. its ability to sequester metalions such as Ca2+ and Fe3+. After being bound by EDTA, metal ions remain in solution but exhibit diminished reactivity. EDTA is produced as several salts, notably disodium EDTA and calcium disodium EDTA. The compound was first described in 1935 by Ferdinand Munz, who prepared the compound from ethylenediamine and chloroacetic acid (22). Today, EDTA is mainly synthesised from ethylenediamine (1,2-diaminoethane), formaldehyde, and sodium cyanide (22). EDTA reacts with the calcium ions in dentine and forms soluble calcium chelates. EDTA demineralizes dentine to a depth of 20–30 ÃŽ ¼m in 5 min (23). According to Heindorff et al. (24) EDTA influences chromosome breakage by mutagenic agents. In particular, when applied in combination with chemical mutagens, EDTA enhances mutagen-induced aberration frequencies. Furthermore, they reported that EDTA affects the inhibition of DNA synthesis in primary cultures of mammalian cells. This may be due to impairment of enzymes involved in DNA replication. Using single cell gel (Comet)assay, Marins et al. (25) showed that EDTA did not produce genotoxic effects. Iodine potassium iodide (IKI) Iodine was first discovered in seaweed in the early 1800s. Although its exact mode of action is not fully known, it is thought to induce cell death nonspecifically due to the oxidizing effects of free iodine on SH-OH- and NH groups of amino acids and on double bonds of unsaturated fatty acids. Iodine is highly efficient microbicide to a wide variety of bacterial, fungal and viral infections (26). Potassium iodide (KI) is a compound made of 76% of iodine and 23% of the alkali metal potassium by weight. KI is prepared by reacting iodine with a hot solution of potassium hydroxide, the product being subsequently reduced to iodide by heating the dry reaction mixture with carbon. Another form of iodine compounds is IKI. The solution can be prepared by mixing 2 g of iodine in 4 g of KI; this mixture then is dissolved in 94 ml of distilled water (26). Poul et al. (27) assessed the genotoxic effects of potassium iodate in vitro using the alkaline comet assay and the cytokinesis-block micronucleus assay on CHO cells. Results showed that potassium chlorate as well as potassium iodide, bromide and chloride did not induced DNA damage in the alkaline comet assay for doses up to 10 mM. In another study, Hikiba et al. (28) assessed the effect of iodine and iodoform on chromosome aberrations using Syrian hamster embryo (SHE) cells and found that iodine induced chromosome aberrations and iodoform induced no genotoxicity. Using the comet assay and chromosome aberration test to characterize the genotoxic potency of povidone-iodine within 4 h of contact with CHO-K1 cells, Muller et al. (29) found no chromosomal damage. In another study, Hedayati et al. (30) showed that incubation of lymphocytes with (131)I induced genotoxicity, which was reflected by an increase in micronuclei frequency. Genotoxicity of intracanal medicaments Calcium hydroxide Calcium hydroxide [Ca(OH)2 ] was originally introduced to the field of endodontics by Herman in 1920 as a pulp-capping agent. It is a white odorless powder with the formula Ca(OH)2, and a molecular weight of 74.08 (31). Calcium hydroxide has low solubility in water (about 1.2 gL-1 at 25 C), which decreases as the temperature rises. The dissociation coefficient of Ca(OH)2 (0.17) permits a slow, controlled release of both calcium and hydroxyl ions. The low solubility is a good clinical characteristic as a long period is necessary before it becomes soluble in tissue fluids when in direct contact with vital tissues (32). It has a high pH (about 12.5-12.8), is insoluble in alcohol and is chemically classified as a strong base, it main actions come from the ionic dissociation of Ca2+ and OH- ions and their effect on vital tissues, generating the induction of hard tissue deposition and being antibacterial. Ca(OH)2 dissociates into calcium and hydroxyl ions on contact with aqueous fluids. Ca (OH)2 in water has a thixotropic behavior (33). According to Ribeiro et al. (34) calcium hydroxide do not promote DNA damage in mammalian cells. In another study, Ribeiro et al. (35) revealed that calcium hydroxide was not able to modulate alkylation-induced genotoxicity or oxidative DNA damage as depicted by the single cell gel (comet) assay. MTA MTA is a mixture of a refined Portland cement and bismuth oxide and trace amounts of SiO2, CaO, MgO, K2SO4, and Na2SO4 (36). Portland cement is a mixture of dicalcium silicate, tricalcium silicate, tricalcium aluminate, gypsum, and tetracalcium aluminoferrite (37). Gypsum, and to a lesser extent, tetracalcium aluminoferrite are important determinant of setting time (37). MTA contains fewer toxic heavy metals, has a longer working time, and have undergone additional processing/purification than regular Portland cements (36). The MTA powder is mixed with supplied sterile water in a 3:1 powder/liquid ratio and it is recommended that a moist cotton pellet be temporarily placed in direct contact with the material and left until a follow-up appointment (38). Upon hydration, MTA materials form a colloidal gel that solidifies to a hard structure in approximately 3–4h, with moisture from the surrounding tissues purportedly assisting the setting reaction (38). Hydrated MTA has an initia l pH of 10.2, which rises to 12.5 three hours after mixing (39). Using single cell gel (comet) assay, Ribeiro et al. (40) detected no DNA damage after a treatment of cells by MTA and Portland cements for concentrations up to 1000  µ/ml. In another study, Ribeiro et al.(41) demonstrated that regular and white MTA did not produce genotoxic effects at 1 to 1000  µgmL-1 FOR 3 H AT 37 C. Another study using Chinese hamster ovary (CHO) cells indicated that that MTA and Portland cements are not genotoxins and are not able to induce cellular death (42). Braz et al. (43) assessed the genotoxic effects of MTA and Portland cements in peripheral lymphocytes from 10 volunteers by the alkaline single cell gel (comet) assay. Findings failed to detect the presence of DNA damage after a treatment of peripheral lymphocytes by MTA and Portland cements for concentrations up to 1000 mug mL(-1). Camargo et al. (44) revealed that regular and white MTA preparations did not negatively influence cell survival or reactive oxygen species production. Ding et al. (45) show ed that MTA and calcium silicate possessed no genotoxic effect. According to Zeferino et al. (46) MTA as well as Portland cement+15% bismuth oxide were not genotoxic. Genotoxicity of root canal sealers For assessment of the genotoxic potential of any material, it is recommended to perform a series of in vitro tests. At least two assays, investigating different endpoints, shall use mammalian cells. For cytotoxic and bactericidal compounds, as many endodontic  sealers appear to be, care must be taken in the test set up: For a proper evaluation the selected test concentrations used for genotoxic effects must be below the concentrations where toxic effects are found (47). Ørstavik and Hongslo (48) showed that extracts of a synthetic polymer material, based on epoxy-bis-phenol A, induced mutations in Salmonella typhimurium TA 100 as did extracts of the epoxy-bis-phenol A resin alone. Formaldehyde, an active ingredient from one of the ZnO-based materials, induced mutations in both Salmonella typhimurium TA 98 and TA 100. The mutagenic activity of formaldehyde as well as of the epoxy material was reduced in the presence of rat liver microsomes. Schwikl et al. (49) showed that eluates of mixed AH26 were mutagenic, and their genotoxicity was strongly depended on the setting time. The number of mutants after exposure to eluates of unset AH26 was enhanced approximately 7- to 10-fold. However, the mutagenic activity of the mixed material was clearly reduced after a setting time of 1 wk. Physiological saline eluates of the mixed AH26 were not found to be mutagenic. Dimethyl sulfoxide eluates of the liquid component of AH26 elicited mutagenic effects similar to the freshly mixed material; eluates made in physiological saline were barely mutagenic at a 10-fold higher concentration. Leyhausen et al. (50) showed that AH-Plus revealed no genotoxicity and mutagenicity. Epoxy-based sealers are also mutagenic in mammalian cell mutation assays. Ersev et al. (51) showed that silver-free AH26 set for 24 h were weakly mutagenic in Salmonella typhimurium TA100. They further showed that silver-free AH26 might contain small amounts of two mutagenic substances: bisphenol A diglycidyl ether and formaldehyde. Tai et al. (52) revealed that root canal sealers containing formaldehyde and bisphenol A diglyether proved to be not only cytotoxic but also genotoxic. Miletic et al. (53) found no mutagenicity found for AH26 and AH Plus sealers on human lymphocytes in highly controlled conditions in vitro. Formaldehyde is released from some epoxy-based sealers with a maximum after 2 days, even though the amount is much less than that of paraformaldehyde containing zinc oxide-eugenol sealers (54). It was believed that the leakage of formaldehyde and bisphenol- A diglycidyl ether from the epoxy-sealers contributed to the mutagenic effects (49, 55). Formaldehyde is classified as a carcinogen in animals, whereas there exists only limited evidence for carcinogenic effects in man (56). There is also limited evidence for animal carcinogenicity from bisphenol-A diglycidyl ether and no adequate data for the evaluation of human cancer risk for this compound (57). Considering the limited exposure of these compounds from endodontic epoxy sealers and the lack of definitive assessment by the IARC, it seems unlikely that such sealers contribute to an increased risk of cancer in patients. However, the high level of paraformaldehyde in zinc oxide-eugenol. Using Comet assay, Huang et al. () showed that the zinc oxide eugenol-based sealers  (Canals, Canals-N, and Tubilseal) did not always cause a dose-dependent increase in genotoxicity. The resin-based sealers (Topseal, AH 26, and AH Plus) caused a dose-dependent increase in genotoxicity, but no such effect was seen with the calcium hydroxide-based sealer (Sealapex) (47).

Kiwi Ultra Fruit Juice Strategy Analysis

Kiwi Ultra Fruit Juice Strategy Analysis Prabhjot Singh Cheema Ques1 (a): Strategic planning: It deals with the big image of the organisation. It is considered as an organisational activity which is used to set predominance along with focus on energy and resources and strengthening operations. It also ensures that whether the employees and stakeholders are working together for a common goal with the establishment of agreements which intend to show outcomes/results. The most important thing for this plan is it is not a monument, but at end it is way for a firm to achieve its purpose. The main purpose of this plan is setting overall or long term goals for business and achieves those goals. Such a long term plan looks into four or five years in to the future. It also involves stepping back from every day operations and review where business is headed and what its next priorities should. It includes business, its vision, firms identity and the direction in which firm is heading. (b): Operational planning: the operational planning refers to the steps which are to be considered and followed to carry out the organisations goals. Moreover, it is the planning in which strategic goals are broken into small activities and aims which are planned to reach out to vision and goals. This plan is to represents high detail information to direct people in performing everyday tasks. This plan provides who, when, what and how much is required to complete the task. That mean, the strategies which are to be considered with the persons who will be responsible for specific tasks and timelines when the tasks are to be completed with the financial resources available for those strategies. The main purpose of this plan is to provide firm with a clear image of their tasks and responsibilities with referring to common goals and objectives contained in strategic plan. Ques2: (a): considering myself as the CEO of kiwi ultra fruit juice I would make a complete strategic plan by setting goals visions. Three strategic goals in my strategic plan will be: Making a vision to expand the business into other areas of NZ so that company can earn more in slow economy as well. Another mission will be to favourably price the products by reviewing with that of other competitors. The last goal of the company will be to move the brand into some other foreign lands with a complete strategic plan. (b): In order to expand the business the company need to take actions such as the very first action will be to clearly define the market. This seems to be a very simple step. Kiwi ultra juice need to consider the demographics and locations and interest or needs of  customers of that specific location. In this way the company can bring out products which are more preferred by specific located people. Moreover, company can perform market analysis. It will involve more market research targeting customers. Secondly, in order to develop the business internationally, the company should increase their sales in the existing markets as well as they should develop more products than only orange juice. This will bring their company to next level. They should launch products which completely differentiate them from their competitors and develop a new image. Ques3: (A): control process: It is a continuous process. The four steps involved in control process are: 1. Setting up of control standards: every company plan their activities in advance. On the basis of these plans, goals and objectives are fixed for every department and branch. 2. Measurement of performance (Actual): this is the second step in controlling process. Its actual performance is measured against the standard sets. This step will let the management know whether they are working according to the plans or not. 3. Compare measured performance against established standards: this step in the control process is for making comparisons of actual performance with the standards sets. The main purpose of this step is to (a) find out the deviations if in case (b) and know the reasons for such deviations. 4. Take corrective actions: last and most important step in this process is taking corrective actions. Efforts are needed to be made if performance is out or less than the standards (B) Types of control: Feed Forward: in this type of control, deviations are predicted and measured and actions are taken before the occurrence of such errors. If such errors are not measured then the systems will not get output as the firm has desired. Concurrent: this type of control takes place whilst activity is in progress. This process involves regulation of activities which are being carried out ensuring that they conform to the standards of the organisation. It is designed to make sure that employee working activities are bringing the correct outputs and results. Feedback control: this types of control focuses mainly on the output of the organisation after the completion of whole transformation. It is also called as output control or post action. It is also important to note that this step is mostly preferred when other two seems to be more costly or not feasible. (c) Two examples of feed forward control that kiwi ultra juice might use to ensure that its products are of highest quality: 1. In case of kiwi ultra juice organisation should have checked the prices before charging premium charges and also produce more varieties of juice in the market. 2. The company should also have checked the image of its competitors and then they have taken such actions through which they can present their company and products in a better way ensuring the quality of the brand. (d) Using concurrent control to achieve its objective: concurrent control is an ongoing process step in which measures can be taken when the process is working. In case of kiwi ultra juice, company should have changed its premium prices when they realise the charges are high as comparative to other brands. And this will help them to increase their sale and achieve companies objectives. While, in case of feedback control, the company can use the advices of marketing experts researchers and can plan to expand the brand in other foreign lands and can earn good revenue. But in this case company need to make good plans and launch product in a more productive way. Ques4: SIMPLE ORGANIZATIONAL CHART FOR TUCKERS COMPANY:-       Mr. Harnett, president of Tucker Company explained board of directors regarding his reorganisation of company. The company is divided into three divisions as: commercial, military jet engines utility turbines (lab operating) with a VP for every division and individual manager. Each division has their own departments. Ques 5: Mr. Hodge, Head of the laboratory operation and Mr. Franklin, departmental manager of Engineering department, Utility Turbine division had conflicts over the work of tests that were to be carried out for engineering dept. of utility divisions. The main issue was the involvement of Mr. Hodge in the experiments and its design and selection of materials and evaluation process of the experiments. He felt that laboratory should be involved in all department experiments and divisions as well. On the other side, Mr. Franklin did not liked the idea of Mr. Hodge and did not want laboratory to get involved in all such cases. Hence there is a clear conflict between both department managers and over their roles. Moreover, there is also interpersonal kind of conflict. Some of the conflict between both the managers is also due to the organisational structure in past and also due to the personalities of both the heads of the department. Looking on to the organisation, the reason for the rising of the conflicts is extension of facilities of departments to all other departments and divisions. Illustrating this, the laboratory was under Military jet engine division and they have to provide facilities to all departments. The laboratory has more work towards military so it should not inclined more towards other experiments and tests from other divisions. Hence, the work load gets high and then conflicts start between interdepartmental and interdivisions. Because lab manager has to report to military jet engines vice president, it was not separate on its own. Ques6 : New organisational structure for TUCKERS COMPANY: Such a design ensures that department which provides help to other departments of all divisions would not only limit to single division. So, the common department will be able to provide and extend their services to all other divisions and departments. The laboratory will be directly under the control of president and can be named as shared services division department. This can be termed as matrix structure of organisation. The advantage of such a chart would be that this new shared department would be accessible to all departments for all their tasks and can be performed without any bias. The disadvantage of such a division will be that new division formed will be autonomous and even if it had manager like Mr. Hodge who always think of its own rather than company will act in irresponsible manner. Ques7: Centralization versus Decentralization: Centralisation refers to the process in which activities of an organisation are mostly controlled by the top managers. Here, top managers make key decisions with little or no input. They make planning on the basis of decision making and becoming more concentrated within a specific group or location. The environment is more stable as well decisions are significant. Whereas, Decentralisation refers to the process where decisions are mostly made by or delegated to the lower levels of the firm. Managers are mostly close to the action so more of the responsibility is sent towards to them. Companies mostly decentralise for managers to get more of the work done. It helps to motivate them more as well as helps to develop lower level personnel. Mechanistic vs. Organic : Mechanistic refers to clear chain of control an is more formal. This structure runs like a machine and individuals and functions behave more in a predictable way. This structure mostly works well when the environment is certain and even there is little change. People are more willing to obey and corporate and the work is repeating. Production is more. On the other hand Organic structure refers to flat structure. In this the firm uses cross-hierarchical and cross-functional teams. The company has low formalisation and has a comprehensive information network. The company works like a creature. Communication is more horizontal. Ques8: (a): Ans: The tuckers company should be more centralised and mechanistic. The authority of decision making should be handed to the president of the company because most of the managers working in the firm are inclined towards their personal status rather than the companys status. In such a way organisation top level make the decisions and work is carried by lower employees in a more orderly manner. Another reason for the company to be more centralised is the environment is more certain and stable. Mangers like Mr. Hodge and Mr. Franklin had created more conflicts because the decision was in their hands. Such an environment affected the output of the laboratory results. In a centralised and mechanistic structure, organisation runs like a machine. Decisions are more significant. All managers have their clear tasks and roles and divisions which will not make confusion or raise a conflict. (b): Ans: The type of span that would be suitable for the tucker company is wide span of control. The reason behind the wide span of control is there will be fewer managers in the organisation. More the managers, more is the conflict as it can be clearly seen in the tuckers company. Another reason for this is with one or two managers, the employees will be on same level and they can work with each other. All the employees will be delegated clear duties and tasks . Such kind of supervision and control can create more positive friendly environment among all members. So in such a case conflicts would be less among managers and output will be more. REFERENCES:- Management, F., Managment, S., Management, I., Management, P., Marketing, P., Management, M. et al. (2017). BusinessStudyNotes. BusinessStudyNotes. Retrieved 18 January 2017, from http://www.businessstudynotes.com/ Operational planning: the Purpose of an Operational Plan. (2017). Leoisaac.com. Retrieved 18 January 2017, from http://www.leoisaac.com/operations/top025.htm 5-Step Primer to Entering New Markets. (2017). Inc.com. Retrieved 18 January 2017, from http://www.inc.com/karl-and-bill/5-step-primer-to-entering-new-markets.html Steps Involved in Control Process. (2017). YourArticleLibrary.com: The Next Generation Library. Retrieved 18 January 2017, from http://www.yourarticlelibrary.com/management/controlling/steps-involved-in-control-process/53348/ Strategic Management :: Concurrent Control. (2017). Strategic-control.24xls.com. Retrieved 18 January 2017, from http://www.strategic-control.24xls.com/en106

Social System in Gabriel Marquez’s Chronicle of a Death Foretold and Al

Social System in Gabriel Marquez’s Chronicle of a Death Foretold and Albert Camus’s The Stranger â€Å"Like father, like son† the old saying goes. And naturally this is so, for if the parent lacks morals, logically the child will too. Just as parents shape their children, authority figures shape their societies. Authority figures have great impact on the common people, for if they act in dishonest or fraudulent manners, the society considers it acceptable to do the same. Such reflections between authority figures and society are seen throughout Gabriel Marquez’s Chronicle of a Death Foretold and Albert Camus’s The Stranger. With societies constantly looking to authority figures for guidance, Marquez and Camus satirically depict folly in the actions of the leaders in order to criticize the social system and reveal the accepted selfishness that is reflected by the people. In order to completely understand the manner in which authority figures actions become reflected on society, a reader must observe the social system through the eyes of the narrator. Marquez begins Chronicle of A Death Foretold by establishing the town to appear very religious. The novel commences with the townspeople thoroughly preparing for the yearly arrival of the bishop. The whole town arranges for his arrival, bringing him many gifts and animals. Although Marquez establishes the city as consumed in religious dedication, a reader must analyze the thoughts of the townspeople in order to truly understand the society. The individuals of the community make elaborate preparations, not to show their spiritual devotion, but to benefit their personal selves. Each person concerns themselves with receiving a blessing from the bishop. The people seem to be... ...ngs in order to expunge their sins, The Stranger also presents faith as a means to obliterate sins. In both systems, people rely on religion in hypocritical manners. Instead of desiring a spiritual peace, the people have been taught by authority figures, like the magistrate, to use religion in self-interest. Overall, Marquez and Camus break the spiritual, rational, and impartial facades of the authority figures by exposing the idea that; since the leaders of the society were unable to provide a moral structure for their citizens, an accepted form of selfishness unfolded within the societies. The social systems in both novels act as the shadow of the bishop and the magistrate. Like a shadow, the societies follow in the leaders footsteps, for the society lives as a dark reflection of the authority figures who promote selfishness and false public images.

Essay on The Holy Bible - Comparing Identity in the Tower of Babel and

Identity in the Tower of Babel and Creation Stories God recognizes that human beings are not specifically good the moment He creates them; for unlike His other creations, He does not pronounce them as such. But also unlike His other creations, they are the only ones created like something else, like God, in His image. If they are truly to exist and be good, they must become separate from God, as the other creations are separate and categorized. It takes some human action to get them out of the Garden of Eden--specifically, the woman and the man eating the fruit. Unfortunately, they can't do everything on their own. They need some interference from God, namely the flood, to distance themselves further from Him and to separate them individually, from each other. Though the people in the Babel story do not exercise it very well, the ability to name, to define, to separate, and to classify seems like a prodigious power, and even a privilege. To become fully human men must distinguish themselves from God. When God sends the flood. He separates Himself from them by putting the world into their hands, as if to say, "There you go, you're grown up now, you take care of it." The gift of the Earth should be God's last active attempt at separation; from then on the humans should try to separate themselves from Him on their own. But like birds kicked out of the nest who try to climb back up the tree, they try to build the tower to heaven; and once again, God must intervene by creating even greater difference. This time He confuses their languages so they are not only different from God but also different from each other. Both God and mortals understand the tremendous power of language and of naming. For example, at one point ". .... ...er He changes their languages first, and they scatter themselves once they realize they can't understand one another. The former interpretation is probably more accurate, but both show how distance, both physical and figurative, creates difference. And in this case it is a difference that makes teamwork, and the tower which would bridge the gap between earth and heaven, as well as the gap between man and God, impossible. Therefore, by being different from each other, the scattered people of Babel grow even more different from God. Despite the problems that arise from difference (namely conflict), it is necessary for humans to be distinct from one another because they need to obtain identity, both as a race of beings and as individuals, separate and different not only from God, but from one another. Work Cited 1 The Holy Bible, Authorized (King James) Version.

Analysis Network

CIRCUIT SWITCHING AND PACKET SWITCHING 1) INTRODUCTION Telecommunication networks carry information signals among entities, which are geographically for apart. The communication switching system enables universal connectivity. Switches can be valuable asset to networking[1]. Overall, they can increase the capacity and speed of our network. Every time in computer network we access the internet or another   computer network outside our immediate location, our messages are sent through a maze of transmission media and connection devices.The mechanism for moving information between different computer network and network segment is called switching in computer network[2]. Figure 1: Switched network Long distance transmission is typically done over a network of switched nodes. Nodes not concerned with content of data. A collection of nodes and connections is a communications network. Data routed by being switched from node to node. Nodes may connect to other nodes only, or to stations an d other nodes. Node to node links usually multiplexed. However, switching should not be seen as a cure-all for network issues.There are two different switching technologies which are: 1) Circuit switching and 2) Packet switching. 1. Circuit Switching Circuit switching was the first switching technique have been used in communication network. This is due to easy to carry analog signals. Circuit switching  network establishes a fixed bandwidth channel between nodes before the users may communicate, as if the nodes were physically connected with an electrical circuit. The bit delay is constant during the connection, as opposed to packet switching, where packet queues may cause varying delay.In circuit switching, the transmission medium is typically divided into channels using Frequency Division Multiplexing (FDM), Time Division Multiplexing (TDM), or Code Division Multiplexing (CDM). A circuit is a string of concatenated channels from the source to the destination that carries an inf ormation flow. To establish the circuits, a signaling mechanism is used. This signaling only carriers control information, and it is considered an overhead. Since all decisions are taken by the signaling process, the signaling mechanism is the most complex part in circuit switching.Each circuit cannot be used by other callers until the circuit is released and a new connection is set up. Even if no communication is taking place in a dedicated circuit then, that channel still remains unavailable to other users. Channels that are available for new calls to be set up are said to be idle. Telephone network is example of circuit switching system. Virtual circuit switching is a packet switching technology that may emulate circuit switching, in the sense that the connection is established before any packets are transferred, and that packets are delivered in order.Unlike with packet switched networks, we cannot just send a ‘packet’ to the destination. We need to establish and la ter terminate the connection. We need to have some way of transmitting control information, we can either do this in band that the same channel we use for data or out of band which is on a seperate dedicated channel. Phone networks used in band signaling a while ago we could control switching and other functionality by playing tones into the telephone. Today in band signaling is considered unsecure and is not used except for compability with old systems[3]. 2. Packet SwitchingPacket switching  is a communications paradigm in which packets are routed between nodes over data links shared with other traffic. In packet-based networks, the message gets broken into small data packets. These packets are sent out from the computer and they travel around the network seeking out the most efficient route to travel as circuit become available. This does not necessarily mean that they seek out the shortest route. Each packet may go different route from the others. Each packet contains a  "header† with information necessary for routing the packet from source to destination.The header address also describes the sequences for reassembly at the destination computer so that the packets are put back into the correct order. Each packet in a data stream is independent. To be able to understand packet-switching, we need to know what a  packet  is. The  Internet Protocol (IP), just like many other  protocols, breaks data into chunks and wraps the chunks into structures called packets. Each packet contains, along with the data load, information about the IP address of the source and the destination nodes, sequence numbers and some other control information.A packet can also be called a segment or datagram. Once they reach their destination, the packets are reassembled to make up the original data again. It is therefore obvious that, to transmit data in packets, it has to be digital data. The packet switching can broadly be divided into two main categories, first is the virtual circuit approach and other is the datagram approach. In the virtual circuit approach to packet switching, the relationship between all packets belonging to the message or a session is preserved. A single route is chosen between the sender and the receiver at beginning of the session.When the data are sent, all packets of transmission travel one after another along that route. The wide area networks use the virtual circuit approach to the packet switching. The virtual circuit approach needs a call setup for establishing a virtual circuit between the source and destination. A call teardown deletes virtual circuit. After the setup, routing takes place based on the identifier known as the virtual circuit identifier. This approach can be used in the WANs, frame relay and an ATM. In the other approach of packet switching that is the datagram approach, each packet is treated independently of all others.Even if one packet is just a piece of a multi-packet transmission, the ne twork treats it as though it is existed alone. Packets in this approach are known as the datagram. The internet has chosen datagram approach to switching in the network layer. It uses the universal addresses defined in network layer to route packets from the source to destination. In  packet-switching, the packets are sent towards the destination irrespective of each other. Each packet has to find its own route to the destination. There is no predetermined path; the decision as to which node to hop to in the next step is taken only when a node is reached.Each packet finds its way using the information it carries, such as the source and destination IP addresses[4]. 2) HISTORY OF CIRCUIT SWITCHING AND PACKET SWITCHING * Evolution of Circuit Switching Switches are used to build transmission path between telephone set on a flexible basis. Without switches, each telephone set would require a direct, dedicated circuit to every other telephone set in order to be able to communicate. This is a full-mesh physical topology network. Such a full mesh network clearly is resource-intensive, impractical and even impossible, as early experience proved.Circuit Switching were developed for voice communications. Contemporary circuit switches provide continuous access to logical channels over high-capacity physical circuits for the duration of the conversation. In January 1878, the first telephone switch went into operation in New Haven Connecticut. Switching technology had advanced drastically over the intervening decades, yet the basic function had remained the same: interconnect users of telephones by creating circuits between them. Every telephone has a line, or circuit, that connects physically to a telephone switch.In the simple case of both the person making the call and the person being called are connected to the same switch, the caller dials the number of the desired person, the switch checks to see if the line is available, and if it is, the two lines are interconnec ted by the switch. The connection is maintained until one person hangs up his or her telephone, at which time the switch terminates the connection, freeing both lines for other calls. Three characteristics of this type of switching, called â€Å"circuit switching,† are important.First, before the two parties can talk the circuit between them has to be created, and it takes time for a switch to check if a connection can be made and then to make the connection. Second, when a connection has been made, it creates a dedicated connection. No other party can reach either party of a dedicated connection until that connection has ended. Three, since switches are very expensive one accounting policy telephone companies implemented to recover their investment was to institute a minimum charge for every telephone call, generally three minutes.For voice calls that lasted many minutes, a minimum charge did not represent a problem. But communications between computers often last less than seconds, much less minutes. It was difficult to image how circuit switching could work efficiently for computer communications when such a system took minutes to make a connection, created dedicated connections so only one person, or party, could be in connection with another party, and had a prohibitive cost structure. Although these issues were generally understood before the experiments of Roberts and Marill in 1965, they were once again strongly confirmed.The experiments also made it abundantly clear that the problems confronting computer communications were not only with the circuit-switching architecture of the telephone system. Host operating system software of the day assumed there was only one Host and all connecting devices were as if â€Å"slaves. † Hosts were not designed to recognize or interact with peer-level computers; the concept of peer-level computing did not yet exist. Thus, in interconnecting two computers, one had to be master and one slave. The problem only became worse if more than two computers wanted to interconnect and communicate.Nevertheless, the problem of Host software was considered to be solvable if a suitable communication system could be designed and made to work. Fortunately, an inquisitive innovative scientist, Paul Baran, had already explored the problems of circuit switching beginning in 1959. By 1962, he had made his concept of a message-based communication system publicly known. Independently, in 1965, an English scientist, Donald Davies reached the same conclusions as had Baran and would coin its name: packet switching. * Evolution of Packet Switching The concept of packet switching had two independent beginnings, with Paul Baran and Donald Davies.Leonard Kleinrock conducted early research and authored a book in 1961 in the related field of digital message switching without explicitly using the concept of packets and also later played a leading role in building and management of the world’s first packet s witched network, namely the ARPANET. Baran developed the concept of packet switching during his research for the US Air Force into survivable communications networks, first published in 1962, and then including and expanding somewhat within a series of eleven papers titled â€Å"On distributed communications† in 1964.Baran’s earlier paper described a general architecture for a large-scale, distributed survivable communication network. His paper focused on three key ideas: 1) the use of a decentralized network with multiple paths between any two points, 2) dividing complete user messages into what he called message blocks (packets), and 3) delivery of this message by store and forward switching. Baran’s study paved the way for Robert Taylor and J. C. R.Licklider, both wide-area network evangelists working at the Information Processing Technology Office, and it also helped influence Lawrence Roberts to adopt the technology when Taylor put him in charge of developm ent of the ARPANET. Baran’s packet switching work similar to the research performed independently by Donald Davies at the National Physical Laboratory, UK. In 1965, Davies developed the concept of packet switched networks and proposed development of a U. K. wide network. He gave a talk on the proposal in 1966, after which a person from Ministry of Defense told him about Baran’s work.At the 1967 ACM Symposium on operating system principles, Davies and Robert bringing the two groups together. Interestingly, Davies had be chosen some of the same parameters for his original network design as Baran, such as a packet size of 1024 bits. Roberts and the ARPANET team took the name â€Å"packet switching† itself from Davies work. In 1970, Davies helped build a packet switched network called Mark I to serve the NPL in the UK. It was replaced with the Mark II in 1973, and remained in operation until 1986, influencing other packet communications research in UK and Europe[5]. 3) COMPARISON BETWEEN CIRCUIT AND PACKET SWITCHINGCircuit Switching: In circuit switching a message path or data communication path or channel or circuit is dedicated to an entire message block during the process of message transmission. The entire bandwidth is dedicated to the said message as it were, and before any data transmission can take place circuit initialisation and setup has to be done to enable or determine the avalaibility of the link as in trying to make a call using the telephon line for voice messaging or even dial-up procedure where you need to establsih that the line is free for use in the first place; and then have the line engaged all through your time of use.All the message travel through the same path and keep the link engaged all the while when the block of message is been relayed or transmitted. In circuit switching, whole of the data travels along a single dedicated path between the two terminals whereas in datagram switching data is divided into packets an d each of these packets are treated indepently and travel along different paths, source and destination being the same. Circuit switching concept is used in Telephony networks where a dedicated line is assigned to particular connection, the connection in this case is permanent during the connection.Considerable amount of bandwidth is wasted in this process and at a time only one way communication is possible. Circuit switching is done at physical layer whereas datagram switching is generally done at network layer. Circuit switching requires the resources to be reserved before the transmission of data but datagram switching doesn’t require such reservation of resources. Advantages: 1. Fixed delays, because of the dedicated circuit – no interference and no sharing. 2. Guaranteed continous service, also because of the dedicated circuit. . Guaranted the full bandwidth for the duration of the call. Disadvantages: 1. Takes a relatively long time to set up the circuit. 2. Dif ficult to support variable data rates and is not efficient for burst traffic. The equipment may be unused for a lot of call, if no data is being sent the dedicated line still remains open. 3. During crisis or disaster, the network may become unstable or unavailable. 4. It was primarily developed for voice traffic rather than data traffic. Packet Switching:In packet switching the block of data is split into small units with each unit having a sequence number attached to it for orderly identification within a given message block and these different units are usaully sent across the available diffrent links or channels of data transmission from one end to the other end point where they arrvive at different times but have to be assembled together in the correct order at this location via the sequence numbers to get out the original message back without any data degredation occuring as a result of the different paths of transmissions from source to destination.Also no single data channel is dedicated to any given message block in the course of transmission as many units of different messages can be multiplexed and then get demultiplexed at their deffferent destinations correctly since there are codes to differentiate each unit of message, resulting to no conflict at all. Packet switching splits messages into small units and transmitting them to destination using different paths while at the same time keeping tracks or maintaining an orderliness of the units for proper and correct reassembling of the units to get the original message back.Packet switching is generally used in Internet data transmmission where we send data without minding if the link is free or not as far as we are connected and the pieces of information that we sent are then split into smaller units and then sent in packets, with each packets switched through different data channel most times and with no loss at the end. The main advantage of packet-switching is that it permits â€Å"statistical mu ltiplexing† on the communications lines. The packets from many different sources can share a line, allowing for very efficient use of the fixed capacity.With current technology, packets are generally accepted onto the network on a first-come, first-served basis. If the network becomes overloaded, packets are delayed or discarded (â€Å"dropped†)[6]. Advantages: 1. Since packet are typically short, the communication links between the nodes are only allocated to transferring a single message for a short period of time while transmitting each packet. Longer messages require a series of packets to be sent but do not require the link to be dedicated between the transmission of each packet.The implication is that packets belonging to other messages may be sent between the packets of the message being sent from one node to other node. This provides a much fairer sharing of the resources of each of the links. 2. The ability to do statistical multiplexing which can exploit the i nherent â€Å"burstiness† in many data applications and thereby enable sharing of the network resources more efficiently among multiple data streams is a major advantage. 3. Pipelining†- This simultaneous use of communications links represents a gain in effieciency, the total delay for transmission across a packet network may be considerebly less than for message switching, despite the inclusion of a header in each packet rather than in each message. Disadvantages: 1. Packets arriving in wrong order. 2. Under heavy use there can be delay. 3. Protocols are needed for a reliable transfer. 4. Not so good for some types data streams. Real-time video streams can lose frames due to the way packets arrive out of sequence[7]. ) PERFORMANCE ANALYSIS Circuit Switching In circuit switching, a unique connection is used to move data between the two end user[8]. â€Å"Circuit-Switched type networks† are most commonly portions of the ubiquitous telephone networks to which we ar e all accustomed. In these networks, which generally transmit voice or data, a pribate transmission path is established between any pair or group of users attempting to communicate and is held as long as transmission is required.Telephone networks are typically circuit switched, because voice traffic requires the consistent timing of a single, dedicated physical path to keep a constant delay on the circuit. Figure 2: Example of circuit switching Figure 3: Public circuit switching network Subcribers: The device that attach to the network. Subscriber loop: The link between the subscriber and the network. Exchanges: The switching centers in the network. End office: The switching center that directly supports subscribers. Trunks: The branches between exchanges. They carry multiple voice-frequency circuit using either FDM or synchronous TDM.Figure 4: Circuit establishment Basic performance equation for a single link in a circuit-switched network: Let’s consider a system with N cir cuits on a single link, with customers arriving according to a Poisson process at rate ? customers per second, and with successful customers having a mean holding time of h seconds, distributed as a negative exponential distribution with parameter ? = 1/h. If a customer attempting a new call finds all the circuits busy, there are no waiting places, so we’ll assume that the customer just goes away and forgets about making the call.Define the state of our system by the random variable K, where K represents the number of customers currently in the system, then K can take on any integer value in the range from 0 to N. With these assumptions, our model is simply a state-dependent queue, with arrival rate (independent of the state), and service rate i when the system is in state K=i. This is known as an M/M/N/N queue: Markovian arrivals, Markovian service time, N servers, and a maximum of N customers in the system. We can draw the following Markov chain diagram to represent the sy stem.When there are I customers the service rate is i , which is due to the fact that there are i customers, each with a service rate ? , so the total service rate is i. Figure 5: Markov chain diagram Under conditions of statistical equilibrium, the solution is: pi=AiN! j=0NAjj! Observe that this is simply a truncated Poisson distribution and also the result depends on the traffic A, and not the specific values of ? and ?. To establish a path in circuit switching three consecutive phases are required: 1. Connection establishment. 2. Data transfer. 3.Connection teardown. Elements of a circuit-switch node (Figure 6): * Digital Switch: Provides a trasnparent signal path between any pair of attached devices. * Control Unit: Establishes, maintains and tears down connections. * Network Interface: Functions and hardware needed to connect digital and analog terminals and trunk lines. Figure 6: Circuit switch element Packet Switching In packet switching, data are broken into packets of fixed or variable size, depending on the protocol used. The performance of packet switching is called best effort performance.If you transmit from sender to receiver, all the network will do its best to get the packet to the other end as fast as possible, but there are no guarantees on how fast that packet will arrive. Figure 7: Example of packet switching Packet switching is used to optimize the use of the channel capacity available in digital telecommunication networks such as computer networks, to minimize the transmission latency, the time it takes for data to pass across the network. It is also used to increase robustness of communication. These layers are introduced to break down the complexity of communications.The top layer (layer 7) is the layer at user level. As the layers go down, they get increasingly primitive. Layer is most primitive from as it is just binary numbers prepared to be transmit to the end node. Seven layers of open systems interconnection models are shown in ta ble 1[7]: Layer Number| Name| Description| 1| Pysical Layer| Deals with physical connection between nodes in network. | 2| Data Link Layer| Maintaining and optimising actual connection. | 3| Network Layer| Deals with communication of data on a network. | 4| Transportation Layer| Sequencing, error detection and optimisation of communication. 5| Session Layer| Controls the communication between applications running on end nodes. | 6| Presentation Layer| Format data and provides syntaxes for application. | 7| Application Layer| Contains management functions. | Table 1: Layers of open systems interconnection model Every packet contain some control information in its header, which is required for routing and other purposes. Figure 8: Packet data format Initially, transmission time decreases as packet size is reduced. But, as packet size is reduced and the payload part of a packet becomes comparable to the control part, transmission time increases.Figure 9: Variation of transmission time with packet size. As packet size is decreased, the transmission time reduces until it is comparable to the size of control information. There is a close relationship between packet size and transmission time as shown in Figure 9. In this case it is assumed that there is a virtual circuit from station X to Y through nodes a and b. Times required for transmission decreases as each message is divided into 2 and 5 packets. However, the transmission time increases if each message is divided into 10 packets[9].The packet switched networks allow any host to send data to any other host without reserving the circuit. Multiple paths between a pair of sender and receiver may exist in a packet switched network. One path is selected between source and destination. Whenever the sender has data to send, it converts them into packets and forwards them to next computer or router. The router stores this packet till the output line is free. Then, this packet is transferred to next computer or router ( called as hop). This way, it moves to the destination hop by hop. All the packets belonging to a transmission may or may not take the same route.The route of a packet is decided by network layer protocols. As we know there are two approaches for packet switching which are: 1. Datagram switching, 2. Virtual circuit swtiching. 1. Datagram Switching: Each packet is routed independently through network which is also called connectionless packet-switching. Datagram packet switching sends each packet along the path that is optimal at the time the packet is sent. When a packet traverses the network each intermediate station will need to determine the next hop. Routers in the internet are packet switches that operate in datagraam mode.Each packet may travel by a different path. Each different path will have a different total transmission delay (the number of hops in the path may be different, and the delay across each hop may change for different routes). Therefore, it is possible for the p ackets to arrive at the destination in a different order from the order in which they were sent[10]. Figure 10: Datagram packet switching Figure 11: Delay in datagram packet switching There are three primary types of datagram packet switches: * Store and forward: Buffers data until the entire packet is received and checked for errors.This prevents corrupted packets from propagating throughout the network but increases switching delay. * Fragment free: Filters out most error packets but doesn't necessarily prevent the propagation of errors throughout the network. It offers faster switching speeds and lower delay than store-and-forward mode. * Cut through: Does not filter errors; it switches packets at the highest throughput, offering the least forwarding delay. 2. Virtual Circuit Switching: Virtual circuit packet switching (VC-switching) is a packet switching technique which merges datagram packet switching and circuit switching to extract both of their advantages.VC switching is a v ariation of datagram packet switching where packets flow on so-called logical circuits for which no physical resources like frequencies or time slots are allocated shown in Figure 12. Each packet carries a circuit identifier, which is local to a link and updated by each switch on the path of the packet from its source to its destination[10]. A virtual circuit is defined by the sequence of the mappings between a link taken by packets and the circuit identifier packets carry on this link. In VC-switching, routing is performed at circuit establishment time to keep packet forwarding fast.Other advantages of VC-switching include the traffic engineering capability of circuit switching, and the resources usage efficiency of datagram packet switching. Nevertheless, a main issue of VC-Switched networks is the behavior on a topology change. As opposed to Datagram Packet Switched networks which automatically recompute routing tables on a topology change like a link failure, in VC-switching all virtual circuits that pass through a failed link are interrupted. Hence, rerouting in VC-switching relies on traffic engineering techniques[6].Figure 12: Virtual circuit packet switching Figure 13: Delay on packets in virtual-packet switching 5) APPLICATION OF CIRCUIT AND PACKET SWITCHING Circuit Switching 1. Plain Old Telephone Service (POTS) The plain old telephone system (POTS) is the largest circuit switched network. The original  GSM  network is also circuit switched. Prior to the existence of new types of networks, all communication systems had to be built based on the existing telecommunications facilities, which were largely oriented to what the common carriers refer to as plain old telephone service, known as POTS.Consequently, even today, in order to use POTS for data communications, it is necessary to use a modem to convert the data to a form suitable for voice-transmission media. The data transmission rate that can be obtained over a POTS connection is typically les s than 64 Kbps. These rates are adequate for text and audio transmission. However, they are not suf? cient for good quality video transmission in real-time. 2. Switched 56 Service Switched 56 service is a dial-up digital service provided by local and long distance telephone companies. For a connection, a data service unit/data channel unit (DSU/CSU) is used instead of a modem.Switched 56 service uses a 64 Kbps channel, but one bit per byte is used for band signaling, leaving 56 Kbps for data. This service allows the transmission of information over one or two twisted cable pairs to multiple points at a data rate of 56 Kpbs. 3. Integrated Services Digital Network (ISDN) The ISDN was designed in the 1980s to offer end-to-end digital connectivity, while providing the required QoS with data rates in the range of Kbps to Mbps over switched connections. In order to provide even higher data rates, the original ISDN was extended to broadband ISDN (BISDN) (Martin, 1985).The ISDN services are provided to users as ISDN interfaces, each comprising a number of ISDN channels. Using 64-Kbps channels, called bearer or B channels, ISDN provides access to the digital network. ISDN provides lower error rate compared to typical voiceband modems and a relatively high bandwidth data channel[11]. Packet Switching 1. VOIP It is becoming increasingly accepted to transmit delay sensitive data through a packet switched network (rather than circuit switched). There are protocols that can create a virtually real-time environment – which, for voice conversations, is sufficient.Voice over IP is essentially a voice signal encoded into a digital format, being sent through a packet switched network (or possibly any other network) using the Internet Protocol (IP). Over recent years there have been standards developed and supported by major companies including ITU-T H. 323. VOIP has a long way to evolve before it is used as widespread as circuit switched networks, but it is well on its wa y. 2. IPv6 The current protocol that is employed almost everywhere IP (IPv4) has come to the end of its useful life. This is mainly because it has run out of addresses to uniquely identify every non-private computer in the world.IPv6 has been deigned to be more efficient than IPv4 and solve the addressing problems that we face at present. Ipv6 will use 128 bits to address nodes, which provides 2128possibilities (roughly3. 4? 1038). It will incorporate a special ‘option mechanism’ to store optional headers in the transport layer (to maximize efficiency by reducing required space). Finally, Ipv6 will have support for resource allocation, allowing packets to be part of a ‘traffic flow’ which will provide better communication of data such as video/voice streams [VOIP]. 6) CONCLUSION In large networks there might be multiple paths  linking sender and receiver.Information may be switched as it travels through various communication channels. Data networks can be classified as using circuit-switching or packet-switching. Packet switching, which forms the basis of the Internet, is a form of statistical multiplexing in which senders divide messages into small packets. The switching centers receive the control signals, messages or conversations and forwards to the required destination, after necessary modification link amplification if necessary. In computer communication, the switching technique used is known as packet switching or message switch (store and forward switching).In telephone network the switching method used is called circuit switching. Circuit switching  is a technique that directly connects the sender and the receiver in an  unbroken path. In the modern and fast paced world, what we are looking for is efficiency, low costs and reliability and packet-switched networks seems to fulfill most of the criteria that the society is looking for. It would only be a matter of time before circuit switching becomes a thing of the past. 7) REFERENCES [1] Stallings, W. , Data and Computer Communications, 7th ed. 1999, Upper Saddle River, NJ: Prentice Hall. [2] Notes. com, C.What is Switching. Available from: http://ecomputernotes. com/computernetworkingnotes/computer-network/what-is-switching. [3] ABC, T. , Circuit Switching. 2005. [4] Jia, S. and G. Wang. Network performance analysis of packet-switching C;sup;3;/sup; system. in TENCON '89. Fourth IEEE Region 10 International Conference. 1989. [5] Wikipedia, Packet Switching, 2012, Wikipedia. [6] Torlak, P. M. , Telecommunication Switching and Transmission. Packet Switching and Computer Networks: UTD. [7] Heng Zheng Hann, C. Y. Y. , Fareezul Asyraf, Farhana Binti Mohamad, Fong Poh Yeee, Circuit Switching vs Packet Switching, C.Y. Y. Heng Zheng Hann, Fareezul Asyraf, Farhana Binti Mohamad, Fong Poh Yeee, Editor, Wikibooks. [8] Gebali, F. , Analysisof Computer and Communication. Switches and Routers2008, New York, USA: Springer. [9] Kharagpur, I. , Switching Techniqu es: Circuit Switching, CSE. [10] Notes. com, C. Datagram Packet vs. Virtual Packet. Available from: http://ecomputernotes. com/computernetworkingnotes/switching/distinguish-between-datagram-packet-switching-and-virtual-circuit-switching. [11] Dr. Farid Farahmand, D. Q. Z. , Circuit Switching. 2007.

Human Memory Essay

The human memory is that part of our brains that has the capacity to receive, store, and retrieve information. It is comprised of not one but three types: sensory, short term, and long term. Generally, the process involves receiving information or stimulus from the environment. The stimulus is then received by the sensory memory. Then the information, which is converted into electrical impulses, is passed through the short-term memory, and finally, the long-term memory through the neurons. Sensory A stimuli that is sensed or received by one of the five sense organs are received by the sensory memory, which acts as a protective barrier. There are different types of sensory memory, one for each sense organ. For the visual stimuli that are registered by the eyes, the sensory memory is called iconic. Stimuli that passes through the ears are received by the echoic memory. And the haptic memory is for stimuli that are felt or touched. A stimulus reaches the sensory memory between two hundred and five hundred milliseconds after it was perceived. An example of sensory memory is the ability to remember how something looks like even if you were able to see it for only a few seconds. Based on research, sensory memory is able to retain about 12 items in a very short period of time. Interruption in the smooth relay of sensory information can be caused by problems in the neurons . If there are some neurons that do not connect or there are imbalances, then information flow will stop or will be delayed. Short-Term Information that reaches the sensory memory are transferred to the short-term memory. This type of memory allows retention of information for up to 60 seconds. While it can remember information far longer than the sensory memory, the short-term memory can only retain up to five items. To increase the number of items that the short-term memory can remember, studies showed that grouping or chunking the items into three have been found very useful. Short-term memory will degrade if a person experiences chronic pain or drinks constantly. It can be enhanced through aerobic exercises because of the increased oxygen in the brain. Long-Term After information has passed through the short-term memory, it is then transferred to the long-term memory for storage and for retrieval in the future. Contrary to the two previous memories, the long-term memory can hold information indefinitely, sometimes for a lifetime. Information becomes ingrained in the memory through repetition or rehearsal. For instance, the alphabets has been constantly repeated to young children in order for them to remember each letter. As a result, knowledge of them will remain etched in memory forever. Long-term memory degrades through certain illnesses. It can be improved through constant intellectual stimulation and rehearsal. Long-term memory groups information into facts and skills. Facts is further classified into two: the episodic and semantic. As their names suggests, episodic refers to events that are stored in the memory. All the others are stored in the semantic memory. Skills, on the other hand, is about learned information that needs to be recalled to perform certain actions. The processes involved in the long-term memory are retention, retrieval and deletion. Retention is achieved when there is rehearsal. Deletion happens when there is interference. Retrieval can occur through recall and sometimes, through recognition. When the information is remembered from memory, it is called recall. If there are promptings and cues to remember an information, it is called recognition. Interference Interference is defined as the inability to recall an information because certain items or events interfere with the process. Proactive interference occurs when previous learnings will make it difficult to remember new ones. On the other hand, retroactive interference occurs when new learnings make it difficult or impossible to recall past information. While studying, information gets jumbled in the student’s mind because there are too many to recall. To improve absorption and recall, it is important to rehearse the information over a period of time. This could be done by reading the day’s lessons and memorizing the salient points before going to sleep. If the student will make this a habit, he won’t need to cram everything in his head a few days before the exam. By constantly rehearsing, the retention and retrieval will become easy. Other Factors That Could Affect Memory Age is one factor that could make a person forget an information or make it difficult to retrieve it from its storage. Like any other part of the body, the brain also degrades if it is not constantly in use. Injuries, traumas, medicines, and diseases could also affect memory storage and retrieval. For example, a tumor in the brain can interrupt the flow of electrical impulses, resulting to memory loss. Or a trauma caused by accident could result to sensory memory loss in one part of the body. To improve and maintain a good memory, it is always important to keep on exercising the mind as well as the body. When the mind is seldom used, it degenerates. Reading, learning and engaging in intellectual discourses would keep the mind active. References Gailbuck. (2007). Delving Into the Autistic Brain – Part 1. HubPages. Retrieved August 14, 2008, from http://hubpages.com/hub/autism-sensory-processing Human Memory. Retrieved August 14, 2008, from http://www-static.cc.gatech.edu/classes/cs6751_97_winter/Topics/human- cap/memory.html Mohs, R. How to Improve Your Memory. HowStuffWorks. Retrieved August 15, 2008, from