Properties Of Distributed Systems Information Technology Essay

Properties Of Distributed Systems Information Technology Essay A distributed system consists of multiple autonomous computers that communicate through a computer network. The computers interact with each other in order to achieve a common goal. A computer program that runs in a distributed system is called a distributed program, and distributed programming is the process of writing such programs. Distributed computing also refers to the use of distributed systems to solve computational problems. In distributed computing, a problem is divided into many tasks, each of which is solved by one computer The word distributed in terms such as distributed system, distributed programming, and distributed algorithm originally referred to computer networks where individual computers were physically distributed within some geographical area. The terms are nowadays used in a much wider sense, even referring to autonomous processes that run on the same physical computer and interact with each other by message passing. While there is no single definition of a distributed system, the following defining properties are commonly used: There are several autonomous computational entities, each of which has its own local memory. The entities communicate with each other by message passing. A distributed system may have a common goal, such as solving a large computational problem. Alternatively, each computer may have its own user with individual needs, and the purpose of the distributed system is to coordinate the use of shared resources or provide communication services to the users. Other typical properties of distributed systems include: The system has to tolerate failures in individual computers. The structure of the system (network topology, network latency, number of computers) is not known in advance, the system may consist of different kinds of computers and network links, and the system may change during the execution of a distributed program. Each computer has only a limited, incomplete view of the system. Each computer may know only one part of the input. PROPERTIES OF DISTRIBUTED SYSTEMS So far the focus has been on designing a distributed system that solves a given problem. A complementary research problem is studying the properties of a given distributed system. The halting problem is an analogous example from the field of centralised computation: we are given a computer program and the task is to decide whether it halts or runs forever. The halting problem is undecidable in the general case, and naturally understanding the behaviour of a computer network is at least as hard as understanding the behaviour of one computer. However, there are many interesting special cases that are decidable. In particular, it is possible to reason about the behaviour of a network of finite-state machines. One example is telling whether a given network of interacting (asynchronous and non-deterministic) finite-state machines can reach a deadlock. This problem is PSPACE-complete,[39] i.e., it is decidable, but it is not likely that there is an efficient (centralised, parallel or distributed) algorithm that solves the problem in the case of large networks. SECURITY ISSUES IN ADAPTIVE DISTRIBUTED SYSTEMS In the contemporary society, distributed systems have a significant impact on how communication between social, industrial and governmental institutions is achieved. Dealing with the complexity, heterogeneity and dynamics of distributed systems is absolutely among the main concerns of the software industry. In the Internet era, the distribution of information and services on different sites is a common and dominant scenario. Hence, accessing information and services on remote sites requires high-level of system quality: acceptable response time (at least à ¢Ãƒ ¢Ã¢â‚¬Å¡Ã‚ ¬Ãƒâ€¦Ã¢â‚¬Å"near real-timeà ¢Ãƒ ¢Ã¢â‚¬Å¡Ã‚ ¬Ã‚ ); and security mechanisms. These aspects require inherent adaptation of the system to changes in the environment. In the case of ADSs, the challenge to maintain system quality is even greater. In general, security issues in distributed information systems, whether adaptive or not, is already a serious concern. There are many types of threats, among them those occurring during communication and those in the form of unauthorized attempts to access stored information. Solutions proposed to address these problems in distributed systems may contribute to the implementation of security mechanisms in ADSs. On the other hand, if a token ring is used to achieve mutual exclusion in data communication, then a loss of token might be a result of unauthorized monitoring of the token, which is a direct consequence of the distributed system being adaptive and having monitoring component. Moreover, data resubmission might be requested by authorized parties that couldnà ¢Ãƒ ¢Ã¢â‚¬Å¡Ã‚ ¬Ãƒ ¢Ã¢â‚¬Å¾Ã‚ ¢t receive the data. Such a request might also come from malicious intruders that are requesting resubmission of data to get a copy. The kind of environmental changes that can be monitored in ADSs include, but are not limited to, processor and link failures, changes in communication patterns and frequency, changes in failure rates, and changed application requirements. Security metrics indicate the degree to which security goals such as data confidentiality are being met, they propose actions that should be taken to improve the overall security program, and identify the level of risks in not taking a given action and hence provide guidance in prioritizing the actions. They also indicate the effectiveness of various components of a security program. Developing effective security metrics programs has proven to be very challenging. A number of factors have contributed to this collecting the necessary data is difficult and there are no well-established and standardized guidelines. Swanson et al. (2003) identified elements that must be considered in defining effective security metrics, metrics must yield quantifiable information, supporting data must be readily obtainable, only repeatable processes should be considered for measurement, and metrics must enable tracking of performance. Voas et al. (1996) propose a security assessment methodology, called a daptive vulnerability analysis (AVA), which provides a relative measure of software security. The methodology is based on measurement of security weaknesses in terms of predetermined set of threats that are frequently encountered. The resulting metrics may vary with different set of threats and hence the methodology is called adaptive. Its major advantages include, among others, its ability to be customized to application-specific classes of intrusions and the fact that it measures dynamic run-time information. The fact that it is based on a predetermined set of threats is among the major limitations of AVA. Payne (2001) proposes a guideline that should be closely followed in the development a security metrics program. The guideline consists of several steps: clear definition of security goals and objective, decision about what metrics to generate and strategies for generating them; create action plan, and establish a formal program review cycle. Following this guidance enables us to clarify the why, what and how of developing security metrics. In the sequel, we focus on the metrics that should be generated to quantify the level of security threats that could be caused due to monitoring of a target system to achieve the level of adaptation necessary to maintain quality of services. ADAPTIVE DISTRIBUTED SYSTEMS Distributed systems that can evolve their behaviors based on changes in their environments are known as Adaptive Distributed Systems (ADSs). Adaptation usually takes place on different sites in a distributed system and needs to be coordinated. Adaptive systems monitor and evaluate their environments and can adapt their own behaviors when there is a change in the environment. On the other hand, adaptive behavior is the field of science where the underlying mechanisms of adaptive behavior of animals, software agents, robots and other adaptive systems are investigated into. The results from adaptive behavior research are exploited for building artificially intelligent adaptive systems. In this case, we envision distributed systems within the context of artificially intelligent adaptive systems and we therefore believe that the research progress in adaptive behavior will affect the research in ADSs. That is, monitoring, change detection and behavior adaptation components of an adaptive distributed system will become more intelligent in time. An ADS better knows what is happening in its environment by detecting and evaluating the changes in the environments and adjusting their actions to the changes more intelligently. However, the more intelligent and adaptive a distributed system becomes through its monitoring and other components, the more risky it becomes that the intruders act more severely in a distributed environment if the monitoring component is overtaken by them. In the following paragraphs, we are giving a brief survey on ADSs. Leonhardt et al. (1998) indicate that security is an issue that appears where activity is being tracked, namely by the monitoring system they have proposed. For that reason, in this work, we look into the levels of knowledge a monitoring system might eventually have about its environment while becoming more adaptive, and whether the level of knowledge and the properties of the knowledge being monitored would cause any security issues compared to the distributed systems which are not adaptive. Russello et al. (2005) described how adaptation is done for dynamical replication for managing availability in a shared data space. The idea is that if replication is require d, the middleware should offer mechanisms that would allow the application developer to select from different replication policies that can be subsequently enforced at runtime. There is an adaptation subsystem where the environment conditions are monitored. It is detected when to switch to another replication policy automatically. The execution environment conditions which are monitored are cost of communication latency and bandwidth, especially when external monitoring subsystem is used. Silva et al. (2002) developed a generic framework for the construction of ADSs. The model is composed of three main packages. In the monitoring package, system specific parameters, such as processor utilization, in the various hosts of the distributed system are monitored. This package informs the event detection and notification package whenever values of such parameters change significantly. In addition to this, interceptors as used in the CORBA distributed system standards are inserted into the object invocation path. Each time a client invokes a method of an object, the message corresponding to this invocation is intercepted and later re-dispatched to the target object . Using interceptors, the system can extract useful information from each method invocation storing it in a log file for analysis by the event detection and notification package. On the other hand, dynamic configuration package, depending on the type of the event, executes the appropriate algorithm that defines actions that should be taken in order to adapt the application to the new environment condition. As stated in (Al-Shaer 1998), monitoring system can be used to detect and report security violations such as illegal logins or attempts of unauthorized access to files. On the contrary, we argue that if the monitoring subsystem is overtaken by an intruder, the monitoring system can also be used for causing security violations once an intruder has knowledge about login information and file authorizations to be able to report illegal logins and attempts of unauthorized access to resources.

Procedure for Protecting Clients Patients and Colleagues from Harm Essay

The Mayor’s role as the executive of the strategic authority for London is to promote economic development and wealth creation, social development, and the improvement of the environment. The Mayor also has a number of other duties in relation to culture and tourism, including responsibility for Trafalgar Square and Parliament Square. The Mayor has a range of specific powers and duties, and a general power to do anything that will promote economic and social development, and environmental improvement, in London. Before using many of his powers the Mayor must consult with Londoners, and in all cases, the Mayor must promote equality of opportunity. The Greater London Authority Act 2007 supplemented and updated the GLA Act 1999 and granted some additional powers to the Mayor of London and the London Assembly. The Mayor sets out plans and policies for London covering transport, planning and development, housing, economic development and regeneration, culture, health inequalities, and a range of environmental issues including climate change, biodiversity, ambient noise, waste disposal and air quality. These individual plans fit together to help deliver the Mayor’s policies. Between them, these plans must also contribute to sustainable development and thehealth of Londoners. The mayor of London has been accused of failing to deliver on a range of climate change policies during his four-year term in office, as new figures reveal he has spent just half of an  £84m green budget. London’s Green Party assembly member Darren Johnson today revealed that Boris Johnson will have underspent on environmental policies every year since being elected mayor in May 2008, meaning he has used  £40m of a total  £84m budget. But Jones said the mayor ditched the 2012 target because he had â€Å"blown the budget† by investing in eight new hop-on-hop-off Routemaster buses, at a cost of  £11.37m. â€Å"I think his new vanity bus has blown the budget for ensuring all buses are hybrids,† she said. â€Å"Instead of eight prototype buses, we could have had another 96 low-polluting hybrids on our roads. Pound for pound this is a bad deal for London’s environment.† The GLA Act 1999 gives the Mayor responsibility to produce a Municipal Waste Management Strategy for London. London’s Wasted Resource, the first draft strategy for consultation with the London Assembly and functional bodies, was launched on 18 January 2010. A second draft will be published for public consultation in summer 2010, and the final strategy will be published in late 2010/early 2011.

Ethics Of Working With Adolescents - 1633 Words

Ethics of working with adolescents is not simply a response to their conflicts and dilemmas. It involves a complex deliberation of the legal context, as well as the ethical framework, that guides the practice of a healthcare practitioner (Michaud, Berg-Kelly, Macfarlane, Benaroyo, 2010). Ethical considerations for an adolescent include the important components of duty of care, confidentiality, consent, and mandatory reporting (Sigman, Silber, English, Epner, 1997). Sustainable service collaboration between various service providers is essential to provide holistic health and social service (Beadle, 2009). Multiagency work is at the core of providing comprehensive and integrated support services to young people especially those with multidimensional and co morbid issues (Ogenchuk, Sputt, Bally, 2013). Bruun and Hynan (2006) emphasise the need for ‘effective, client-centred, relationship-based practice’ for positive health and wellbeing outcomes in this young group (p. 19). Challenge Identified In my professional capacity as a psychotherapist in private practice, as pointed out in the case study of Amy, working with vulnerable young people is fraught with challenges. My ethical tension surfaced again when Amy shared some of her presenting issues especially surrounding sexuality, sexual abuse and abortion. These topics are rarely discussed openly in muslim communities and a taboo topic at best in most Asian cultures. An important study conducted by Sawleshwarkar etShow MoreRelatedDeveloping An Alternative Punishment For Adolescents1345 Words   |  6 Pagesalternative punishment for adolescents can be considered as a positive opportunity for the treating adolescent, society, community and the criminal justice field. Ethics helps management differentiate what is considered right or wrong within the management and the process implemented for the treating adolescents. There are many branches considered within the study of ethics. Metaethics can be consid ered as the language, methods, logic structure, or reasoning when interpretation ethic terms. IdentifyingRead MoreEthics Code1617 Words   |  7 Pages The Ethics Code is intended to support us in differentiating between suitable and deplorable behavior in regards to all individuals. When working with adolescents and children, the guidelines become a little more ambiguous. Adolescents require consent from a legal guardian in most cases to seek treatment, but confidentiality permits some information discussed from being released to the parent that requested the treatment. When working with youth the primary focus can include not only theRead MoreThe Need For Proper Crisis Intervention Is Essential For The Healthy Functioning Of The Individual984 Words   |  4 Pagesunit (Kanel, 2014). When working with an adolescent client who is presenting the signs of illicit drug use, it is always a good idea to explore the family dynamics. Adam being only 15 years old is still in the transitional stage where his actions are still closely linked to his family of origin. Teens are often dealing with the conflicts of wanting to be independent from their parents, yet realizing their parents are providing for many of their wants and needs. Adolescents like Adam often find peersRead MoreAdolescence, in modern society is the transition from childhood to adulthood. Known as a time of600 Words   |  3 PagesDuring this process, both boys and girls undergo an adolescent growth spurt that typically begins about two years earlier in girls than in boy. The principals signs of sexual maturity that end the puberty are the spermache, for boy, occurring between the ages of 10 to 13.5, the menarche, for girls, occurring between the ages of 9 to 15, also accompanied with the development of se xual organs. In addition of those previous changes, the adolescent’ brain also undergo significant structural changes forRead MoreQuestions Of Ethics: Mental Disorders698 Words   |  3 PagesResearch: Questions of ethics One of the most serious ethical grey areas arises when conducting research upon individuals with serious mental disorders. First and foremost, their ability to give consent may be in doubt. Coupled with the fact that the subjects in question are underage and may be in physically unstable conditions, the questions of ethical consent grow even dicier. This is the challenge faced by researchers conducting scientific studies of treatments that could be useful for patientsRead MoreCognitive Behavioral Therapy ( Cbt ) And A Family Systems Approach1242 Words   |  5 Pagescontrast an individual approach involving cognitive behavioral therapy (CBT) and a family systems approach. Definitions and descriptions of studies involving both approaches will be provided, and a comparison will be made. Finally, a discussion of the ethics of both studies will be discussed. Two Approaches to Treatment Individual Approach: Cognitive Behavioral Therapy CBT CBT is defined as a form of mental health based counseling, focusing on errors of cognition and perception. It usually involvesRead MoreResearch Regarding Children And Adolescents Essay1400 Words   |  6 PagesResearch regarding children and adolescents have raised a series of ethical concerns in the ethical community. Front and foremost and confidentiality and when to breach confidentiality the third parties involved in risky behaviors from adolescence. Confidentiality is a non-absolute importance in the counseling and psychology practice because of the knowledge when and when not to breeze confidentiality still considering the legal and ethical obligation, most professional counselors if I colleges ourRead MoreThe American Counseling Association Is The Resource That Can Help Your Development As A Future Counselor779 Words   |  4 Pagesfacilitate my development as a future counselor. After I get my LCPC in the state of Maryland, I want to counsel children and adolescents with severe psychological trauma. The ACA website has an entire section on ‘trauma and disaster’ for children through adolescents. The American Counseling Association’s fact sheets provides various symptoms for children and adolescents that are experiencing trauma. According to the American Counseling Association’s Traumatology Interest Network and facilitatorRead MoreThe Ethical Problems Of The Models Of Autonomy And Discipleship1393 Words   |  6 PagesIntroduction Ethical problems present conflicts of the models of autonomy and beneficence. Adolescents as well as minors present a particular complication, which is struggling with autonomy. Healthcare providers are torn between their own moral codes that may lack consistency in their actions and opinions. The prescription or act of seeking out contraception or birth control is taken as an example of a common ethical dilemma. According to Duvall, â€Å"Adolescence is a complicated period of emotionalRead MoreObservational Ratings Of Therapist Interventions1268 Words   |  6 PagesExternalizing (delinquent and aggressive) and Internalizing (withdrawn, anxious/depressed, somatic complaints) symptoms.† Lastly, the Family Environment Cohesion and Conflict subscales which is a self-report measure that is completed separately by both the adolescent and the parents. It is a 90 true or false questionnaire regarding family home life. Following a set of core principles as a general rule of thumb could better assist clinicians in performing an intervention as extensive as MDFT, which is

Essay on Janie’s Courageous Voice in Their Eyes Were...

Janie’s Courageous Voice in Their Eyes Were Watching God Through her use of southern black language Zora Neale Hurston illustrates how to live and learn from life’s experiences. Janie, the main character in Hurston’s Their Eyes Were Watching God, is a woman who defies what people expect of her and lives her life searching to become a better person. Not easily satisfied with material gain, Janie quickly jumps into a search to find true happiness and love in life. She finally achieves what she has searched for with her third marriage. Unfortunately, however, after years of a happy marriage, Janie accidentally kills her husband during an argument. Her town forces her not only to deal with the grief, but to prove her innocence to a†¦show more content†¦Soon after they move to a new town, Eatonville, Joe concentrates his time and thoughts on being the mayor and becoming powerful, not towards Janie. One evening, as the town gathers for the grand opening of its general store, Joe denies Janie the chance to make a speech, even though the crowd wants one: â€Å"‘Thank yuh for yo’ compliments, but mah wife don’t know nothin’ ‘bout no speech-makin’. Ah never married her for nothin’ lak dat. She’s uh woman and her place is in de home’† (43). Janie, very hurt and embarrassed, does not tell Joe of her feelings, but instead keeps them to herself. This non-confrontational attitude toward her marriage shows how easily Janie lets Joe control her with his authority: â€Å"‘Ah hates disagreement and confusion, so Ah better not talk. It makes it hard to get along’† (57). Instead of working out her anger with her husband, an important quality in any working relationship, Janie keeps quiet and lets the frustration and emotion build within her. As their marriage grows, so do Janie’s opinions and her ability to express them. She starts to stand up to Joe when they get into arguments, although Joe continues to refuse to see or speak with her. As Joe grows ill, and close to death, Janie forces him to listen to what she has to say: Naw, you gointuh listen tuh me one time befo’ you die. Have yo’ way all yo’ life, trample and mash down and then die ruther than tuh let yo’self heah ‘bout it. Listen,Show MoreRelated Voice and Language in Their Eyes Were Watching God Essay example2794 Words   |  12 PagesVoice and Language in Their Eyes Were Watching God      Ã‚   In one way or another, every person has felt repressed at some stage during their lives. Their Eyes Were Watching God is a story about one womans quest to free herself from repression and explore her own identity; this is the story of Janie Crawford and her journey for self-knowledge and fulfillment.   Janie transforms many times as she undergoes the process of self-discovery as she changes through her experiences with three completelyRead More Janie from Their Eyes Were Watching God, Gatsby from The Great Gatsby, June from The Joy Luck Club, and Edna from The Awakening1727 Words   |  7 PagesJanie from Their Eyes Were Watching God, Gatsby from The Great Gatsby, June from The Joy Luck Club, and Edna from The Awakening In most of the worlds greatest literature, there have been introduced countless courageous characters and triumphant victories. These characters have the power to father strength from distress and grow brave by reflection. Such characters as Janie from Their Eyes Were Watching God, Gatsby from The Great Gatsby, June from The Joy Luck Club, and Edna from TheRead MoreThe Harlem Renaissance By Zora Neale Hurston1896 Words   |  8 Pagesnovelist who was not only an inspiration to those surrounding her, but also the world as she became known as an earlier version of a feminist but in her eyes, didn t consider herself one. Her writing provided a desperately needed feminine voice in a movement that was dominated by men. She inspired and encouraged other novelists to be courageous and go on a personal journey to reveal individual identity. Hurston was very unique, she was interested in showing off her individual principles, which hadRead More Liberation in The Awakening and Their Eyes Were Watching God3709 Words   |  15 PagesLiberation in Kate Chopins The Awakening and Zora Neale Hurstons Their Eyes Were Watching God With few exceptions, our male dominated society has traditionally feared, repressed, and stymied the growth of women. As exemplified in history, man has always enjoyed a superior position. According to Genesis in the Old Testament, the fact that man was created first has led to the perception that man should rule. However, since woman was created from man’s rib, there is a strong argument that woman