Circuit Protection and Polyphase Motors Assignment

Circuit Protection and Polyphase Motors - Assignment Example These techniques result in a high arc voltage to control over current and voltage during a fault in operation. Types of Air Blast Circuit Breakers: The Air blast circuit breakers can be divided into the following three types: (a). Axial Blast ABCB (b). Axial Blast ABCB with Side Moving Contact (c). Cross Blast ABCB Construction: (a). Axial Blast ABCB The axial blast air ABCB consists of two contacts; one is fixed and the other is movable. The fixed contact has an arcing chamber with a spring loading mechanism, and a nozzle orifice over which the movable contact rests under the normal closed condition. In case a fault arises, a high Figure 1.Axial Blast ABCB (Courtesy:www.electrical4u.com) air pressure in the arcing chamber causes the spring to deform. This produces an effect of lengthening and cooling of the air column in the chamber which pushes out the movable contact. As a result of these changes an arc voltage is produced which is much higher than the system voltage. The disparit y in voltage levels results in the quenching of the arc produced. (b). Axial Blast ABCB with side moving contact: Figure 2. ... As a result, an arc is drawn between the fixed and movable contact, which is passed over to the arcing electrode. This causes the surge to be quenched. (c). Cross Blast ABCB Figure 3. Cross Blast ABCB (Courtesy:www.electrical4u.com) The cross blast ABCB has a fixed blast pipe. The moving contact’s movement is perpendicular to the direction of the air blast from the blast pipe. An exhaust chamber having arc splitters is fitted on the same alignment as the blast pipe. When the movable contact is detached from the fixed contact an arc is established. High pressure air coming from the blast pipe enters the exhaust chamber after passing through the contact breaker, forcefully taking the arc into the exhaust chamber. This results in the quenching of the arc. 1. b. OIL-FILLED CIRCUIT BREAKER Working Principle: The oil-filled circuit breaker is one of the oldest types of circuit breakers. It employs mineral oil as the insulating medium to quench the surging arc. The fixed as well as t he movable contacts are immersed in oil; as a result the arc forms a bubble in the oil. The energy of the arc is utilized to decompose the oil into hydrogen gas. As a result arc quenching is obtained. Types of Oil Circuit Breakers: Oil circuit breakers can be broadly classified into two categories: (a). Bulk Oil Circuit Breaker (b). Minimum Oil Circuit Breaker (a). Bulk Oil Circuit Breaker Construction: Figure 4. Conceptual view of the Bulk Oil Circuit Breaker. (Courtesy:www.electrical4u.com) The bulk oil circuit breakers employ transformer insulating oil as the insulating and arc quenching medium. The current carrying contacts (fixed and movable) and the earthed parts of the circuit breaker are placed in a large quantity of oil in a closed tank or vessel. The oil

Wright Brothers Research Paper Example | Topics and Well Written Essays - 2250 words

Wright Brothers - Research Paper Example While the efforts to design and develop flight can be traced to periods before the 19th century when humans were imitating birds in flight, it is 19th century and early periods of 20th century, which witnessed real and tangible efforts that culminated to controlled and powered flight (Helfand and Banerjee, 2011). Subsequent years have seen rapid advancement in the aviation industry with better and advanced flights being developed. These flights have advanced technological capabilities and comfort. They are more comfortable, fast, and come with more attractive designs. The quest to realize controlled and powered flight began in earnest in 1891 when Otto Lilienthal worked to design a glider that can fly (Dixon-Engel and Jackson, 2007). He was the first person to design a glider that would fly a person, as well as being able to fly relatively long distances. He studied aerodynamics and he wrote a book that was later used by the Wright Brothers in their designs. The year 1891also saw Sam uel Langley building a plane model called aerodrome. Although his efforts to develop a powered flight failed, he made important contributions that would help in developing powered flight in the future particularly by Wright Brothers (Anderson, 2004). In 1894, Octave Chanute undertook the invention of airplanes after being inspired by Otto Lilienthal. He designed several aircraft; the Herring was a particular aircraft that he designed and was the most successful deign and was the basis for the design of Wright biplane (Howard, 1998). He also published a book in 1894 called â€Å"Progress in Flying Machines†. This book contained all the technical knowledge about aviation at that time. The Wright Brothers this book as the basis of their experiments. It is important to note that Chanute was in constant contact with the Wright Brothers and made regular comments on their technical progress. Wilbur Wright and Orville Wright were deliberate in their quest for flight as evidenced by t he fact that they spent many years learning all the early flight developments (Dixon-Engel and Jackson, 2007). They also read all the literature published up to that time about flight. Because of the knowledge that they acquired by reading and learning about flight, they started to test the early theories with kites and balloons. They also spent considerable amounts of time in learning and testing the shapes of gliders and how gliders could be controlled. The year 1903 witnessed a breakthrough in design and development of flight (O'Hern and Mayo, 2006). Wright Brothers were the first to sustain controlled flight, powered flight. Wright Brothers are the two American brothers who are credited as the earliest successful aviation inventors and pioneers. They are credited with inventing and developing the first successful airplane in the world, as well as making the first sustained, controlled, and powered heavier-than-air human flight on 17 December 1903 (Howard, 1998). Historians agree that even though the Wright Brother were not the first in building and flying experimental aircraft, they were the first in inventing aircraft controls that made possible the fixed-wing powered flight. In particular, they achieved a major breakthrough that other inventors had not achieved; they invented a three-axis control that enable the pilot to effectively steer the aircraft and at the same time maintain the aircraft’s equilibrium (O'Hern and Mayo, 2006). The significance of this method became standard in aviation and remains standard mainly on all kinds of fixed-wing aircraft. While the experimenters of the time were emphasizing on developing powerful aircraft engines, the Wright Brothe

Budget Planning Assignment Example | Topics and Well Written Essays - 250 words

Budget Planning - Assignment Example It is thus important that organizations compare the work completed with its objectives rather than merely analyze budgets on calendar basis. For instance, one may spend 90% of the allocated resources in doing a shoddy work or completing only 80% of the stipulated work, notwithstanding that the spent amount may fall within the projected calendar period. One could also run under budget on calendar basis. That is, the same proportions of the budget and work may be covered as expected while running under budget on calendar basis due to delays and breaks. The implication here is that there could have been slips in work schedule. While under budget implies that one performs below the planned budget, over budgets means that the planned budget has been surpassed. Proper planning and implementation of budget would thus lead one to as close to the budget as possible (Barr & McClellan, 2011). Excessive under budget could therefore suggest a situation in which one did not spend enough in specifi c areas to grow and protect business or establish a project. On the other hand, constant over budget performance could suggest that one is in danger of running out of resources and business. It is thus vital that work is done as planned to avoid both under and over budget both of which have their negative effects and implications on task implementation and completion (Article Library,

Service Delivery System Essay Example | Topics and Well Written Essays - 500 words

Service Delivery System - Essay Example The service delivery systems are linked from the manufacturing process to the distributing process. This system looks after the every aspect for delivering the goods or services with the consumer satisfaction as the main goal. The service delivery system works as a link between the producer and the consumer. The goods which are being monitored by this system may be the goods, jobs, technologies or software too. There is no limit for the working of the service delivery system. In every industry, the efficient service delivery system is required to look after the delivery issue of the services offered by that particular industry to their clients. The service delivery system examines the input as well as the output in the industry or organization. It takes feedback of the customers and tries to solve their problems. Then these problems are taken into account to remove these problems future. This system leads stress on the choice and requirement of the consumer.

Promoting Wellness and Resilience Essay Example for Free

Promoting Wellness and Resilience Essay This paper deals with promoting wellness and resilience for individuals with intellectual and developmental disabilities (IDD). First, a model of wellness and resiliency is presented. Then, recommended intervention activities that promote resilience and wellness are discussed. Lastly, prevention and education activities are proposed. Wellness and Resiliency Model Studies on wellness and resilience models among individuals with IDD appear non-existent and very few have been written about counseling methodology. Most focus on a cognitive-behavioral approach to psychotherapy (CBT). Therefore, a paradigm must be created that combines CBT and an evidence-based model of wellness. Myers, Sweeney, and Witmer (2000) define wellness as â€Å"a way of life oriented toward optimal health and well-being, in which body, mind, and spirit are integrated by the individual to live life more fully within the human and natural community. Ideally, it is the optimum state of health and well-being that each individual is capable of achieving† (p. 252). â€Å"Resilience refers to positive adaptation, or the ability to maintain or regain mental health, despite experiencing adversity† (Herrman, Stewart, Diaz-Granados, Berger, Jackson, Yuan, 2011, p. 259). Myers and Sweeney (2005) created a model of wellness called The Indivisible Self which is based on Adlerian principles. This model delineates five areas of wellness: physical, essential, social, coping, and creative. Physical well-being is further divided into two areas: exercise and nutrition. Essential wellness is broken down into four components: spirituality, self-care, gender identity, and cultural identity. Social felicity is divided into two parts: friendship and love. Coping is divided into four aspects: realistic beliefs, stress management, self-worth, and leisure. Creative fitness is broken down into five elements: thinking, emotion, control, positive humor, and work (Myers and Sweeney, 2005). Recommended Intervention Activities That Promote Resilience and Wellness As  the IDD population tends to be of lower socioeconomic status (as adults), placed in residential facilities, and highly medicated, physical health is a vital component of overall wellness. Physical fitness can be maintained through exercise programs. A community-based program described by Lante, Walkley, Gamble, and Vassos (2011) provided health and psychosocial benefits to participants. In the area of essential wellness , spirituality plays an important part in the lives of most. IDD individuals should be allowed to attend worship services or participate in other activities cultivating the spiritual nature. Watts (2011) proposes utilization of Special Religious Education for People with a Developmental Disability (SPRED), defined as â€Å"†¦symbolic catechesis where formal instruction is supplemented or completely replaced by visual, aural, sensory, and physical stimuli (p. 237). In the area of self-care, individuals can be taught tasks to their fullest level of independence. Gender identity can be explored through modified sex-education curriculums exemplified by The Facts of Lifeand More by Walker-Hirsch (lesliewalker-hirsch.com, 2014). Social well-being is a necessary component of wellness among those with IDD. Friendship and love are very possible and should be encouraged. Community groups, such as The Gathering Place and Pathfinders, provide a venue and activities for the population (welcometowesley.com, 2014; gracenc.org, 2014). Dating sites such as Special Bridge provide access for individuals with IDD a chance to meet and date others with IDD (specialbridge.com). CBT can be utilized to help disabled individuals in the area of coping. Irrational beliefs can be explored and replaced with more realistic views. Stress management techniques can be taught. Self-worth can be explored and improved (Lee, 2004). Leisure skills and interests can be explored and improved upon through systematic testing and development (Kreiner and Flexer, 2009). Creative fitness can be cultivated through activities that involve thinking, particularly critical thinking. Handling emotions and controlling behavior can be taught via dialectical behavioral therapy (DBT) (Rizvi, Steffel, and Carson-Wong, 2013). Work needs can be met through sheltered, supported, and/or competitive employment. In North Carolina, the Division of Vocational Rehabilitation provides services and referrals to service providers (ncdhhs.gov/dvrs, 2014). Proposed Prevention and Education Activities Education and prevention can focus on training individuals, families, caretakers, and facility staff. If those who are in contact with the population everyday can be educated as much as possible, the level of wellness and resilience in persons with IDD should increase. IDD clients can learn about healthy eating and exercise through objective plans adjusted for functioning level. For instance, individuals with autism can read a social story (The Gray Center, 2014). Individuals, families and staff can be trained on proper nutrition by registered dietitians who can develop meal plans (American Dietetic Association, 2009). The importance of gender and sex education, spirituality, and cultural identity can be taught to those working with people with IDD. Gender and cultural identity and sex education can be taught to individuals with IDD through modified curriculums or incidental learning. Social skills, coping mechanisms, and creative pursuits can be taught to individuals. Families and facilities can learn what coping mechanisms are effective for clientele. Identified Strategies to Promote Community Resources Families in particular can be directed to community resources. Many resources exist for individuals with IDD. Brochures, information about service providers, and government resources can be given to families and higher-functioning individuals. Providing links to websites for organizations such as The Arc and managed care organizations such as Coastal Care can be a good starting place (thearc.org, 2014; coastalcarenc.org, 2014). References Beange, H., Lennox, N. (1999). Health targets for people with an intellectual disability. Journal of Intellectual Developmental Disability, 24(4), 283. Retrieved from http://ezproxy.library.capella.edu/login?url=http://search.ebscohost.com.library.capella.edu/login.aspx?direct=truedb=aphAN=2731367site=ehost-livescope=site The gathering place. (2014). Retrieved May 18, 2014, Retrieved from http://welcometowesley.com/connect/special-needs/ The gray center: What are social stories. (2014). Retrieved May 18, 2014, Retrieved from

Requirements for Healthcare Organization | Case Study

Requirements for Healthcare Organization | Case Study TASK I A SUMMARY ON THE NEEDS AND EXPECTATIONS OF CONCORDIA HEALTHCARE LTD. RELATIVE TO: I. Internal Organizational needs First and foremost, ABC Concordia Healthcare Ltd. Requires that the staff, partners, members, directors will consider and respect the Equality and Diversity Guidance and Policy. This organization is committed to delivering quality health care services to the clients without prejudice on them due to race, nationality, sex, sexual orientation, disability, religious affiliation, marital status, employment status and political opinion and characteristics. All clients should be treated equally and fairly. Professionalism on the part of the staff, partners, members and directors should be observed. No client should be discriminated; instead, promotion and accessibility of health care services should always be the ultimate mission of everyone. Quality healthcare services will result to the increasing demand by diverse clients. The ABC Concordia Healthcare Ltd. will be sought by the community and the clients they serve. A good name will be established for and in behalf of ABC Concordia Healthcare LTD. II. External Needs of ABC Concordia Healthcare LTD. To achieve the goal of this organization, that is the promotion of equal opportunity and accessibility of quality healthcare services to all clients, they are also considering their external needs. A. Meeting clients’ needs Appropriate steps must be considered to be able to meet the diverse needs of clients. 1. Identify the needs of clients who come from different communities. Clients come from different communities with different cultural background and upbringing. So, they also have different needs. These needs have to be catered well. 2. Formulate the policies and procedures that will be undertaken to meet clients’ needs. Policies should be done regularly because these are guides for decision making. Policies encourage coordination and integration of actions and plans within and across functional areas of an organization. The policy making process involves the following: a. Identifying the problem b. Formulating the policy c. Implementing the policy d. Evaluating the results 3. Specify the services that should be provided to the following group of clients: a. Clients with a disability b. Clients who are unable to communicate effectively in English c. Carers, children and the elderly d. Members of religious groups e. ethnic groups, nationalities f. Lesbian, gay or transgender people B. Communication Plan To avoid miscommunication, the ABC Concordia Healthcare Ltd. also provides the following: 1. A Communication Plan is prepared to disseminate the policies and procedures to ensure that all services are provided to the clients. 2. Steps to be followed and the requirements to be accomplished are also given to access the healthcare services 3. Orientation and training for the employees, members, partners, staff, and directors are done for effective implementation of the plan. FAIRNESS AND JUSTICE A just and fair treatment can be the strongest asset in any organization especially if there is competition. ABC Concordia Healthcare LTD. has laid some policies with emphasis on the following: a. Dealings with third parties – this organization does not unlawfully discriminate other Healthcare service providers. b. Dealings with contractors- ABC Concordia Healthcare Ltd. engages contractors on the basis of their skills, experience and ability. There is no discrimination whatsoever based on age, gender, marital status, race, religion, etc. c. Employment – Job applicants are treated equally and fairly. Recruitment and selection procedures and terms and conditions of employment, training opportunities, promotion and transfer, grievance and disciplinary process, demotions, dress code, bonus schemes, work allocations and other employment related activities are carefully relayed to employees and applicants. d. Recruitment and Selection- ABC Concordia Healthcare LTD ensures that the workforce is: Taken from the widest pool of qualified applicants . Job openings are open to all. Effort is directed towards the dissemination of the information that will reach all interested applicants. Employment opportunities are based on personal merit and fitness. Performance is considered in this regard. Priority is given to applicants from all sections of society especially the underrepresented in the workforce. This is where fairness is evident. No one is discriminated simply because he belongs to the underprivileged and the handicapped. ABC Concordia Ltd. has lawful exemption (genuine occupational requirements) to be used suitable to meet the special needs of a particular group. People with special needs are those coming from different ethnic and cultural background; gender (especially the gays, lesbians and transgender people), carers, etc. Recruitment agencies of ABC Concordia Healthcare Ltd. know the requirements not to discriminate. Fair and equal treatment should always be borne in mind. There is a wholesome working environment respecting the employee’s beliefs and diverse background. Terms and conditions of service for employees comply with anti-discrimination legislation. The organization identifies the diverse training needs of the workers. A plan is made which includes the details of the training to be provided, who will be trained, and when the training will be provided. Those identified are informed of this quality and diversity and training plan. Acts of unlawful discrimination on any of the forbidden grounds by employees, partners, members, directors will be subjected to disciplinary action. Appropriate action is imposed to any person employed who commits unlawful acts of discrimation. All complaints will be investigated in accordance with the grievance procedure of the organization. ABC Concordia Healthcare Ltd. will monitor and record equal opportunities and information about staff and all employees. These pieces of information will be used exclusively for equal opportunities monitoring and have no bearing on opportunities and benefits. The organization will provide equal opportunities to the Human Rights Services Commission as required in relation to personal and clients under the terms of the legislation. Operation review of the organization will be conducted twice a year. Remediation will be imposed on non-compliance under the policy to equal opportunities. THE IMPACT OF PREJUDICE AND DISCRIMINATION ON INDIVIDUAL AND GROUP 1. Prejudice and discrimination are acts of disrespect on the uniqueness of every individual. â€Å"Individual differences should be recognized although human beings are similar in many ways.† 2. Prejudice and discrimination may cause stress. â€Å"Typical causes of stress are: new work procedures, work overload, differences between the organization and employees values, frustration and role ambiguity. Workers are likely to suffer mental and physical symptoms as a result of pressure.† 3. Prejudice and discrimination hampers the individual’s desire to grow and to achieve his goal. If an individual is constantly discriminated, he loses his self-confidence. Thus, he can’t perform his task well. When prejudice is felt in an organization like a Healthcare Provider, the client would lose his motivations to get well and to become fit again. Nobody encourages him and nobody values his human dignity. 4. Discrimination and prejudice are non-humanitarian actions. This will deprive the act of getting people work together to accomplish desired goals and objectives at minimum cost and maximum profit.† 5. Commitment is obtained through kindness. Hence, organization should be fair and impartial, free from biases in dealing with employees and clients. 6. In Maslow’s Hierarchy of Needs, belongingness, love, affection and acceptance are among the basic needs of man. When there are discriminations of whatever nature, then there is no love, affection and acceptance. 7. Discrimination and prejudice is against the Civil Rights of people. â€Å"Civil rights guarantees fair and equal treatment for all people regardless of race, religion, ethnic origin, age, sex, sexual orientation, disabilities, or personal beliefs.† On July 2, 1964, Pres. Lyndon B. Johnson signed into law the Civil Rights Act of 1964 prohibiting discrimination based on a person’s race, color, national origin, religious beliefs and sex. PROPOSED IMPROVEMENTS TO ADDRESS GAPS IN THEIR SYSTEM PROCESS 1. Plan for review and monitoring on the compliance of equality and diversity issues should be prepared Separate from that of the communication and training plan. 2. Team meetings should be done regularly to track and discuss the progress of implementation. A special meeting may be convened also at any time to consider urgent matters. 3. Roles and responsibilities of the persons manning the organization should be clearly specified like: a. Director/ manager b. Staff c. Employees d. Other support personnel 4. Time scales for planning, implementation, monitoring and evaluation should be clarified. 5. Periodic audit on the organization’s financial status is important. This is one component of the overall performance management framework. As an initiative is implemented, the outputs and outcomes are monitored, refined and then evaluated. 6. Policies should be revisited from time to time. Substantial amendments maybe necessary to ensure the stability of the organization. 7. Human resources are important in any organization. Performance assessment should be conducted as basis for planning skill enhancement training and updating. 8. Facilities and other material resources should be equally allocated. Insufficient or outmoded materials may affect the efficacy of attainment of the organization. 9. Facts should be gathered and use them as supporting evidences in order to analyze the programs and services and in turn may serve as guide for proper actions.

Buffer Overflow Attacks And Types Computer Science Essay

Buffer Overflow Attacks And Types Computer Science Essay Abstract Buffer Overflows are one of the main reasons for problems in a computer system. Statistics in this report have shown that the number of attacks in the past 20 years is increasing drastically and it is buffer overflow which is also rated the most occurring attack. This paper basically provides the various prevention techniques for Buffer Overflow attacks, like Canaries, DEP and ASLR, and more which have been deployed and are working well to a certain extent. Introduction It is the job of the compiler to check for errors or vulnerabilities in the code. In C, the compiler is not so very efficient to detect these logical errors. The simplest form of a buffer overflow attack would be as follows:- char buf1[5]; char buf2[10]=A1B2C3D4E5; strcpy(buf1,buf2); The above 3 lines of code are compiled without any error by the C compiler as there are no syntactical errors. But logically we are copying a string of 10 chars into a buffer which can hold only 5 chars. This might be a small typing error on the programmers side, but results in an attack which can overwrite the data which might have been stored in the memory location next to the space allocated for buf1. This is Buffer Overflow. Its types are explained in the section below. Buffer Overflow Attacks types. Buffer Overflow Attack as defined by Kramer (2000) occurs when a program or a process tries to force more data into a buffer than it is actually intended to hold. The simplest examples to explain this is the program above, but in laymans terms, let us assume 2 jugs, one with a capacity of 2 litres and another of 1 litre. If you try to empty the 2litres of water into the jug which can hold only 1 litre, you spill 1 litre of water. This attack can have many consequences on a system like incorrect results, security breach or even a system crash. Posey (2005) explains the different types of Buffer Overflow attacks. There are basically two kinds of buffer overflow attacks: 1. Heap-based attacks and 2. Stack-based attacks. In Heap-based attack the attacker floods the memory space which is actually reserved for the program. This attacks is not exactly easy as it feels, hence the number of attacks with respect to the heap are very rare. In Stack-based attack, the attacker takes advantage of the stack, a part of the memory reserved for the program to store data or addresses. The attacker then partially crashes the stack and forces the program execution to start from a return address of a malicious program address which is actually written by the attacker. Statistics Fig 1. Buffer Overflow Statistics Statistics from the National Vulnerability Database(2011) show the occurrence of Buffer overflow attacks. It ranges from 1989 to 2011. The graph is declining in the last 3-4 years, but experts say that there is a possibility that it may rise again. Prevention Techniques Some host based mechanisms to prevent Buffer Overflow Attacks are mentioned below: Detection Elimination: Kuperman(2005) says detection and elimination of the vulnerable code is necessary before someone takes advantage of that code. In this technique there are ways in which software searches for some specific type of code. This is known as Source Code Auditing. Vernon (2003) in his WhitePaper has mentioned techniques and ways how it is done. Kuperman has also mentioned about a group, OpenBSD Group, a group which audits the source code free of cost for a BSD based Operating System. The time taken for analysis is large and the expertise of the volunteers determine their efficiency. Complier Modifications: A technique to avoid buffer overflow attack is to modify the way the data is stored in the memory. StackGuard is a type of a complier which can be used to add gaps in the memory in between, these gaps are known as Canaries. It works in the following way: whenever a function gets a return call, it reads the canary on the stack and check for any modification. If it finds the canary is modified it understands it is under attack. (Kuperman, 2005). Another Complier, ProPolice uses pointers to address memory locations. ProPolice is also an enhancement concept of StackGuard. Frantzen Shuey (2001) in their article have mentioned about StackGhost. StackGhost is a unique technique which was developed by Sun Microsystems. It detects the change in return pointers without actually affecting the program. It effect on the throughput is also negligible. This made attackers much more difficult to do a buffer overflow. Array Bounds Checking: Cowan et al(2000) have explained each time an operation needs to be performed on an array, we can do the boundary checking. If boundary is reached it wont allow writing into the array, thus avoiding the buffer overflow. Similarly we can write a code to check the size of each buffer when writing. If the destination buffer is bigger than the other which is to be copied, then its ok or dont allow it. This technique although might work, but is very costly to implement as it will delay the actual process. Non-Executable Stack: Fritsch (2009) explains marking of the stack as Non-Executable can help stopping Buffer Overflow. But this in turn also stops genuine programs from executing directly from the stack. Sanders (2009) had also mentioned the same technique. The article mentioned that Microsoft had included a security feature in its new service pack for Windows XP (it was Win XP SP2). This was known as DEP (Data Execution Prevention). DEP is of 2 types: Hardware and Software. In Hardware DEP some parts of the memory were marked as Non-Executable by the processor. But again this was a bit tricky as not all processors supported Hardware DEP. Software DEP on the other hand watches the exception thrown by program and checks whether they actually belong to the program. Address Space Layout Randomization: Wagle (2003) has mentioned that earlier the attacker used to insert a large number of nop instructions, to work around the memory location. ASLR randomly allocates memory locations to the code and data, thus making it difficult for the attacker to find the instructions. Proof Carrying Code (PCC): Necula (1997) says PCC is a technique which checks the properties of the program, and the code and also checks its security policy and determines whether it should allow it to execute it or not. SmashGuard: Kuperman(2005) has explained this technique uses a modification of the normal call ret instructions. Whenever a call instruction is encountered along with the actual entry of the return address on the stack another entry on the data stack within the processor. Then when it encounters the ret instruction it matches both the return addresses. If it matches it goes ahead with the execution else if a match is not found then it terminates the program. Also no changes are made to the data. This is a technique which works well with Brute Force Attack. Split Stack: Kuperman (2005) has explained that Split Stack or Secure Address Return Stack (SAS) is a proposed technique to prevent buffer overflow attack. In this technique two software stacks are used, one for control information and another for data information. Hence even if an attacker gains access to the data stack, he cannot affect the control stack. Although it might need to read and write from 2 stacks it is worth the time. Write Correct Code: Cowan et al (2000) writes, the best way to avoid any kind of attack if to write good and correct code. It is a humans tendency to write and forget the code, but that same code can be checked by someone else as well. The above mentioned prevention techniques are only few of them which are available; there are many techniques available for prevention against Buffer Overflow Attacks and various other attacks. Risks Fritsch (2009) in another article has explained the way to bypass ASLR protection. He explains there exists a flaw in the random number generation for ASLR. He explains it is not so very difficult to predict the randomization address. Writing a program which will try and brute force the memory location till it finds the correct one breaks the ASLR protection. Symantec Architect Mr. Whitehouse (2007) had mentioned the problem of ASLR in Windows Vista. Research by Mr. Bojinov (2011) shows pre-linking can help in implementing ASLR on Android phones. He has introduced retouching which is similar in design to prelinking. Also crash stack analysis is introduced which uses crash reports on the local device to prevent brute-force attacks. Conclusion This report includes what exactly are buffer overflow attacks, the defenses mechanisms which can be build up to prevent against them. Buffer Overflow attacks are on the top when discussing about penetration issues or buffer related vulnerability issues. Earlier it were only professionals amateurs who were trying buffer overflow attacks, but now the situation has changed, a small keyword search Buffer Overflow Attack Programs returns results with detailed tutorials and description to perform it. Also the National Vulnerability Database shows that Buffer Overflow attacks have reduced in the past 3 years, but no one knows when situations might change.