An Introduction To Network Topology

An Introduction To Network Topology In the context of a communication network, the term topology refers to that way in which the end points, or stations, attached to the network are interconnected or it is the arrangements of systems in a computer network. It can be either physical or logical. The physical topology refers that, a way in which a network is laid out physically and it will include the devices, installation and location. Logical topology refers that how a data transfers in a network as opposed to its design. The network topology can be categorized into bus, ring, star, tree and mesh. Hybrid networks (They are the complex networks, which can be built of two or more topologies). Bus Topology A Bus topology is characterized by the use of a multi point medium. A long and single cable acts as a backbone to connect all the devices in a network. In a bus topology, all computers or stations attach through the appropriate hardware interfacing known as a tap, directly to a bus network. Full duplex operation between the station and tap allows data to transmit onto the bus and received from the bus. A transmission from any station propagates the length of the medium in both directions and can be received by all other stations. At each end of the bus is a terminator, which absorbs any signal, removing it from the bus. Nodes are connected to the bus cable by drop lines and taps. A drop line is a connection running between the device and the main cable. A tap is a connector that either splices into the main cable or punctures the sheathing of a cable to create a contact with the metallic core. A bus network work best with a limited number of computers. Advantages Bus topology can install very easily on a network. Cabling will be less compare to other topologies because of the main backbone cable laid efficiently in the network path. Bus topology suited for a small network. If one computer fails in the network, the other computers are not affected they will continue to work. It is also less expensi ve than star topology. Disadvantages The cable length will limited and there by limits the number of stations. If the backbone cable fails, the entire network will goes down. It is very difficult to trouble shoot. Maintenance cost is very high in a long run. Terminators are required for both the ends of the cable. Ring topology The ring topology the network consists of dedicated point to point connection and a set of repeaters in a closed loop. A signal is passed along the ring in one direction, from device to device, until it reaches its destination. It may be clock wise or anti clock wise. When a device receives a signal intend for another device, its repeater generates the bits and passes them along. As with the bus and tree, data are transmitted in frames. As a frame circulates past all the other stations, the destination station recognize its address and copies the frame into a local buffer as it goes by. The frame continues to circulate until it returns to the source station, where it is removed. These topologies are used in school campuses and some office buildings.

Transmission Electron Microscopy Coursework Example | Topics and Well Written Essays - 3000 words

Transmission Electron Microscopy - Coursework Example With the support of ray, diagrams explain how the images were obtained. Your explanation must include comments about the location and use of the objective and selected area apertures. A TEM consists of condenser lenses to focus the electron beam on the specimen, an objective lens to form diffraction in the BFP (Back focal plane) and the image in the image plane, and other lenses to magnify the image or the diffraction pattern on the screen. In order to obtain images in TEM, we either focus on the central spot (direct beam), or on the scattered electrons (diffracted beam). This is done by inserting an aperture (selected area aperture) into the BFP of the objective lens followed by selecting the appropriate beam. Bright field image (Figure 1) The given micrograph depicts a dark MgO crystal on a light and bright background. The topography on the face of the crystal is very clear. Such an image is called a bright field image and has a very high contrast. ...The parts of the crystal in Br agg orientation appear dark, and the amorphous parts of the crystal are bright. The objective diaphragm is adjusted in such a way that an aperture appears in the back focal plane of the objective lens, allowing only the direct beam to enter and blocking the diffracted beam. The objective aperture, when inserted, controls the collection angle. The placement of the SAD (selected area aperture) is critical as it should be adjusted to obtain only the direct beam in this case. Darkfield image (Figure 2) The micrograph in figure two depicts a bright MgO crystal on a dark background. Such an image is obtained by selecting only the scattered electrons using a selected area aperture, enabling them to reach the image plane. The electrons that are not in the direct beam are selected to form a dark field image. The objective aperture is moved sideways to select the un-scattered electrons. This method is of high utility in case of observing certain specific crystallographic orientations of the s pecimen. The dark field image can also be obtained through another method, called centered dark field operation. In this case, the objective aperture is not shifted and the primary/direct beam is used instead. "The beam is tilted in order to allow only the scattered/diffracted electrons to go through the objective aperture (William and Carter 2009). Selected area diffraction pattern SAED (Figure 7) The given micrograph clearly depicts the symmetry of the lattice of MgO crystal through a selected area diffraction pattern. Selected area diffraction patterns are obtained by inserting the SAD aperture into the image plane of the objective lens and aperture on the optic axis in the middle of the viewing screen (William and Carter 2009).

Social Promlem project on Internet Addiction Essay

Social Promlem project on Internet Addiction - Essay Example Moving further, we will look into various types of internet addiction. After this, we will be exploring the effect of gender difference on the internet addiction. Furthermore, the discussion would be led to the causes and the development of the internet addiction. Last, but not the least, we will be looking over various treatment options for the internet addiction. So we can say, in general terms, that addiction is the process of getting habitual to the use of something. In the same connection, internet addiction is, in layman terms, the habitual use of internet or being compulsively occupied with the use of internet. "Technical addictions... non-chemical (behavioral) addictions which involve human-machine interaction. They can either be passive (e.g. television) or active, (e.g. computer games) and usually contain inducing and reinforcing features which may contribute to the promotion of addictive tendencies". (Griffths, 2000) Various experts have also called it cyber addiction. "Cyberspace Addiction: an addiction to virtual realms of experience created through computer engineering... Some cyberspace addictions are game and competition oriented, some fulfill more social needs, some simply may be an extension of workaholicism". (Suler, 1999) All in all, internet addiction, with whatever term it may be referred, is the excessive use of internet to the extent that a person become compulsively engaged in using the internet. Types of Internet Addiction The internet addiction can be classified into a number of typologies. However, the most commonly used typology among the scholarly circles is that based on the usage. On this basis, the internet addiction can be divided into following types: Addiction for Internet Sex Addiction for Games over Internet Addiction for Making Money over Internet Addiction for Chat Addiction for Web Surfing This typology has been adapted from the works of Young (et al. 1999) and Davis (2001). Addiction for Internet Sex According to some estimates, the total worth of the online sex industry is somewhere between 1 and 5 billion US Dollars. Moreover, the sex industry over internet has become one of the major contributors among the total revenue generated through the paid websites (McDonald, 2001). There are also some estimates that the highest search queries on various search engines, such as Google and Yahoo etc, are related to pornography, especially among teens. The internet is heavily with the sex related material. That includes, sex related text (stories), images, video, audio stories and entire DVD format full length

Ben Mikaelsen’s Countdown :: Mikaelsen Countdown Essays

An Essay on Ben Mikaelsen’s Countdown      Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚   Countdown is a book written by Ben Mikaelsen and was first published in 1996.   It has a total of 248 pages and published by the Hyperion Books for Children company.   This book is mainly about sending the first teenager in space.   And it is also about finding how a young coward becomes a village warrior.     Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚   This story takes place in Big Timber, Montana and in Kenya, Africa.   The setting starts off in winter and fourteen-year-old Elliott Schroeder is busy working around his family farm.   On the news, NASA announces the first Junior Astronaut program and youth all around the country will get a chance to become the first teen in space.   Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚   Meanwhile, in Kenya, Africa, a young fourteen year old Masai, Vincent Ole Tome returns from tending to his family farm also.   Vincent was no ordinary boy either, his father had sent him to the â€Å"wood school† which is similar to regular school in America.   With the education he had received, many boys disliked him and named him a coward for not working as hard in the family farms.   Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚   Getting back to Elliott, many things occurred since the announcement of the Junior Astronaut program.   Elliott is chosen to become to first teenager in space and begins his nine month training along with his alternate, Mandy Jane Harris.   This was it, the only chance that Elliott Andrew Schroeder was going to become a national hero and the only thing in his way was Mandy.   Because of that he developed a disliking towards her which almost costed them their privilege to go to space.   Then Elliott realized that his disliking had to reasonable justification and they became the best of friends for the last four months of training.   Then the day came, when Elliott was really going to become the first teen in space and his only duty was to speak to anyone on earth throughout NASA’s space mission.   Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚   While all of this was happening in America, in Kenya, Africa, Vincent is now being tested by the elders of his village along with all other young Masai boys to find who is the bravest of them to become a warrior.   Leboo, a not so close friend of Vincent, tries to tear Vincent’s spirits down by naming him a coward.

Public Policing Versus Private Security

Public Policing Versus Private Security Kayla Cook CJA/500 November 8, 2009 Mrs. Jancie Graham Abstract Public policing and private security have several distinct differences. Public policing is the ability to enforce the law and maintain order in society. Private securities are paid agencies that perform the protective and loss-prevention duties not handled by police officers. Yet public policing and private security offers the same services and duties. These services and duties are performed to achieve some of the same goals. Both serve as leaders in their line of work.The leadership requirements are regulated by two different standards. They both share a positive relationship with the criminal justice system. This relationship could be enhanced if the two would partnership with one another. This could help them combine their essential policies for the current role they perform now. Public policing and private security will continue to grow and work together in the future. This pap er will also describe and discuss the importance of a comprehensive security plan, and its key components. The Differences between Public Policing and Private SecurityPublic policing is the ability to enforce the law and maintain order in society. Private securities are paid agencies that perform the protective and loss-prevention duties not handled by police officers. Public policing and private security have several distinct differences. Public policing does the following: 1) maintain order, 2) performs community service, 3) detect crime, 4) handle crime, and 5) prevent crime, 6) traffic control, 7) stop and question an individual, 8) search individuals and their personal belongings, 9) conduct interrogations, and 10) arrest an individual.Private security does the following paid duties: 1) serves as an escort, 2) patrol housing and business areas, 3) serves as guards at gates, 4) transport valuables, 5) security training, 6) screening of personnel for employment, 7) technical coun ter surveillance, 8) security consultation, 9) install alarm systems and 10)offer private security vaults (Reid, 1996). The Similarities between Public Policing and Private Security Public policing and private security offers some of the same services and duties. These services and duties are performed to achieve some of the same goals.In this way they are able to assist each other in performing these services and duties. Public policing and private security offer the following services and duties: 1) crime prevention, 2) crime control, 3) assist is emergencies, 4) training, 5) conduct searches, 6) involved in community events, 7) offer security, 8) monitor specific area, 9) provides protection, and 10) they both have legal powers. Both public policing and private security agencies are held accountable for their actions. Neither escapes criticisms from outside sources.Our society needs the services and duties that both provide to help ensure the safety of our freedom and our propert y (Walker, & Katz, 2011). The Differences between Public Policing and Private Security Leadership Roles The difference between public policing and private security leadership roles are the standard requirements for leadership. The requirement for leadership in public policing is regulated by the government and civil service. The only requirement for leadership in private security is to lead by example. This is because private security agencies are privately owned and they do not have a set required standard.The Relationship of Public Policing and Private Security with the Criminal Justice System The relationship of public policing with the criminal justice system is to prevent crime and provide justice to the public. The relationship of private security with the criminal justice system is to prevent crime and provide justice to its employees. They both share the same relationship with the criminal justice system. The relationship would be work more effective if law enforcement offic ers and private security agencies would work together along with the criminal justice system to prevent crime and provide justice to the public and private employees.The Essential Policies for Public Policing and Private Security Public policing and private security have several distinct differences in their essential policies. The essential policies for public policing are: 1) Hierarchical- there are many different official and formal levels of public agencies positions. 2) Civil service- civil service examinations are given to chose only the most qualified personnel based on merit. 3) Apolitical- the government gives the policies to public policing to execute. 4) Impartial and fair- the treatment of all citizen using government services are to be fair and just. ) Public affairs-oriented- focus is given to the management of public agencies and organizations. 6) Public-service oriented- profit is not a motive the serve the public. 7) Publicly funded- tax revenues fund these public a dministrations. 8) Publicly documented- all citizens can review administrative records and financial documents. 9) Accountable to the public- at anytime legislative and judicial review can be done to public administration. The essential policies for private security are: 1) Private enterprise- goal is to complete a private obligation instead of a public one. ) Private or corporate ownership- private organizations are owned by private individuals, groups, or stockholders. 3) Competitiveness- the organization may be in competition with another organization with the same product or service. 4) Profit incentive- normally the incentive is to generate net profit unless it is a nonprofit private organization. 5) Financing regulated by market price- the ability to sell the product or service is based on revenue. 6) Privacy of information and records- limited information is proprietary and the property of the owners. ) Accountability to owners and stockholders- instead of being accountable t o the public, the organization and its employees are held accountable to the organization’s owners. 8) Some freedom in selection and termination of employees- civil service rules do not regulate the organization ability to hire or terminate employees. 9) Freedom to regulate work methods and organization- the organization is not regulated by civil service rules (Ortmeier, 2009). The importance of a Comprehensive Security Plan and Its Key Components The security plan must also specify the persons who have access to security areas, and it must specify the various components necessary for physical security, such as barriers, lighting, alarm systems, fire protection systems, locks, and communications. It must detail full instructions for the guard force. These instructions must contain both general orders applicable to all guards and special orders pertaining to specific posts, patrols, and areas. There must be provision for emergency situations. Specific plans for fire, flood, st orm, or power failure should be part of the overall plan of action.You should also specify people to call in an emergency. After the security plan has been formulated and implemented, it must be reexamined periodically for flaws and for ways to improve it and keep it current with existing needs. Circulation of the plan should be limited and controlled. It must be remembered that such a plan, however well conceived, is doomed from the outset unless it is constantly and carefully supervised (Fisher, Halibozek, & Green, 2008, 36 Conclusion Public policing and private security are major components in the criminal justice system.The mere existence of both public policing and private security helps our communities feel safe. Once the two merge and work together, more problems can be solved to prevent crimes. This partnership will be form when the importance of each other’s responsibilities and roles are identified. Law enforcement agencies are slowly coming to realize the benefits of a partnership with private security can be since 9/11. This was just one of the many examples of how effectively public policing and private security can work together.In the future, public policing and private security will continue to work together to prevent crime and provide justice to all. References Fisher, R. J. , Halibozek, E. , & Green, G. (2008). Introduction to Security (8th ed. ). Burlington, MA: Butterworth-Heinemann. Katz, C. M. & Walker, S. (2011). The Police in America: An Introduction (7th ed. ). New York, NY: McGraw-Hill Ortmeier, P. J. (2008). Introduction to Security: operations and Management (3rd ed. ). Upper Saddle River, NJ: Pearson/Prentice Hall. Reid, Sue (1996). Criminal Justice (4th ed. ). Madison, WI. Brown & Benchmark.

I Am A Student Of East Stroudsburg University - 887 Words

I proceeded to walk down the aisle slowly becoming aware of the acrobats doing summersaults in my stomach. With such great prestige I heard the announcer’s voice, â€Å"Gerdwine Bourdeau.† Still in displacement of what had just occurred, rivers of joy rushed down my face. In quick pursuit, I shook President Welsh’s hand, turned my cheek and gleamed a smile towards the camera. In an instant flash the proudest moment of my life quickly became a realization. As of August 2016 I would be a graduate student of East Stroudsburg University. All the tears of joy and stressful nights would eventually become memories I tap into over lunch with a group of alumni friends. The ceremony quickly came to an end. Myself as well as hundreds of students rushed in search of their families. I had become overwhelmed in the confusion to only hear a lonely voice over the crowd shout in creole â€Å"Gerdwine, Gerdwine!† Moments later I stood in front of my first love, my parents. They gazed with admiration and joy, as I stared into their eyes and seen hard working immigrants from Haiti. Raising seven children wasn’t always easy, they worked day in and day out hiking 12 flights of stairs in a Brooklyn apartment building. All to make sure their children received an education that they were unable to obtain. Following in the footsteps of my parents, the past four years at ESU, I reflected the diligent work, dedication, leadership and motivation of my parents. A nervous but bubbly outgoing freshman soon climbedShow MoreRelatedGraduation Speech On The State Exams1460 Words   |  6 Pagesat East Stroudsburg University. As the years and assignments progressed, I developed a set of writing weakness and strengths that still shape the way I write today. Additionally, I have had many opportunities to experience the different styles of writing available. Both of those factors will help me achieve the rigorous goals that I have set for myself and this class. From a simple sentence during elementary school to a comprehensive research report in college, during my years as a student I haveRead MoreMy Career As A Career745 Words   |  3 Pageswant to do with their degree, I am definitely one of those people. One of the careers that I thought was interesting to me was a career as a exercise physiologist. Exercise physiology interests me because it does not seem boring like they are doing something different with a patient everyday like administer test one day and the next day customized a exercise program for that client. Many exercise physiology are on their feet most of the days which I like because I would hate sitting at a desk all

Major Depression Disorder by Anna Grace Tadlock - Free Essay Example

Sample details Pages: 3 Words: 901 Downloads: 5 Date added: 2019/04/15 Category Psychology Essay Level High school Topics: Depression Essay Did you like this example? Hi my name is Anna Grace Tadlock, and I have major depression disorder. I am 17 years old and my life is going good now. I found out I had major depression disorder when I was four years old. Don’t waste time! Our writers will create an original "Major Depression Disorder by Anna Grace Tadlock" essay for you Create order My mom walked out on me when I was two years old and my real dad began abusing me mentally and physically since then. I havent had the best of childhood, but I make the best of it now. I am still struggling with my past today. If I see something that reminds me of the things that happened to me, I have flashbacks, so bad to the point where I play it back in my head. I feel so worthless at points my life feels fake, and I believe its a fantasy thats soon going to end. I feel as if my whole life is just a dream its never going to end, as if my entire life is a lie, nothing really happened. As I look in the mirror, I realize this is real, this isnt my imagination. The way he hit me, the way he touched me, and the way he spoke to me, changed me instantly. I wasnt an innocent quiet girl just trying to keep hidden, I was trying to survive the terror and hurt I was going through, I knew if I talked I wouldnt of have been safe any longer. Even though, all this happened the biggest depression that I went through was losing my siblings. I tried my best to keep them safe, but it looks like I have failed them. I always wondered, what it would of been like if I was never born, or if I was born to a different family. The challenge that I took leaving them was hard, I still cry at night when no one is watching, or I think about the good times we had, it makes me more mad at myself than I am at my real parents. Its a struggle not harming myself everyday, living with this burden on my shoulder is hard itself. I dont know whether to forgive them and try to let it go, or confront them about the pain they put me through. Sometimes I think, I believe its more o f my fault than its theres. When I hear someone talk about my past, I think of hurting myself, like there blaming it on me for what I went through. Just hearing about what they did sends chills down my spine, like ive been shot but really havent. Everyone says I need to talk to a counselor, but I feel like talking about it just makes it worse than it already is. Now im in a home where they tell me they love me but know one can truly love me unless I love myself, and I cant honestly say I dont love myself because my life isnt where I want it to be. I question God even though I know I shouldnt, but the questions I ask is serious, like why did I go through this, how come I dont see other families go through it. I guess the real question is WHY ME? Why cant anyone answer that question, no one has a suggestion on the situation. When I hear someone yell at someone it reminds me of the yelling that went down in my home, how I used to run to other peoples house begging them to help me. The cops couldnt even save me, I was alone, no one to call for a shoulder to lean on. I needed help at the hardest time and not a soul to come. When I finally had the courage to tell, no one believed me. Not a soul to lend a hand to pick me up. Depress ion is not a phase, its a disease. Its like screaming when nobody hears. Its to be falling apart, without anyone noticing. Depression is a serious disease, over 5,000 teens, ages 15-24 kill themselves every year over major depression. The more we suffer today is worse than the 1960s its more pain not spoken out like its supposed to be. Depression is living in a body that fights to survive, with a mind that tries to die. Depression is like drowning, except you can see everyone around you breathing. It feels like everyone is moving on with their lives while I am stuck here, in this hole that I cant climb out of. When you see my scars, dont tell me to stop hurting. Dont tell me it is stupid because you do not know what I am going through. No one will ever understand the pain that I feel everyday of my life. Every thought is a battle, every breath is a war, and I dont think im winning anymore. Everyday it gets harder. Everyday its like a nightmare progressing on. Everyday is another prayer echoing through my bones asking god to take me now. Everyday I hurt more. Everyday it gets more unpredictable. Everyday I feel inside like Im dying more and more. Everyday as I laying in bed, im wondering whens the day god was going to take me home. Ive never felt so much pain that it has caused me these past years. I think god for being on earth and for letting me to continue to tell my story. THE END.