2,610 research outputs found
HIGH PERFORMANCE LAN INTERNETWORK DESIGN.
No full textThe author discusses the requirements of a versatile LAN internetwork design, and proposes a high-performance, fault-tolerant internetwork architecture. The major design goal is to preserve an LAN's characteristics, such as high capacity, low queuing delay, packets in sequence, low error rate, etc. , in the LAN internetworking environment so that high performance is achievable. The new architecture can support both packet and fast circuit switching. It is efficient for various applications with a wide range of channel holding times.</p
An Interactive Tool for Teaching and Learning LAN Design
No full textIt is often difficult to motivate students to learn local area network (LAN) design because many students appear to find the subject rather dry, technical and boring. To overcome this problem the author has developed a software tool (named LAN-Designer) that gives students an interactive learning experience in LAN design concepts. The LAN-Designer is suitable for classroom use in introductory computer networking courses. This chapter describes LAN-Designer and its effectiveness in teaching and learning LAN design. The effectiveness of LAN-designer has been evaluated both formally by students and informally in discussion within the teaching team. The feedback from students indicates that the development and implementation of LAN-Designer were successful. It also discusses the impact of LAN-Designer on student learning and comprehension.</jats:p
An Interactive Tool for Teaching and Learning LAN Design
No full textIt is often difficult to motivate students to learn local area network (LAN) design because many students appear to find the subject rather dry, technical and boring. To overcome this problem the author has developed a software tool (named LAN-Designer) that gives students an interactive learning experience in LAN design concepts. The LAN-Designer is suitable for classroom use in introductory computer networking courses. This chapter describes LAN-Designer and its effectiveness in teaching and learning LAN design. The effectiveness of LAN-designer has been evaluated both formally by students and informally in discussion within the teaching team. The feedback from students indicates that the development and implementation of LAN-Designer were successful. It also discusses the impact of LAN-Designer on student learning and comprehension. </jats:p
Handover on a Highway LAN
No full textHighway Local Area Networks (LANs) require small cell sizes in order to meet the demands for increased capacity which is induced by the large number of users in small areas. As smaller cells are deployed, the number of cell boundary crossings increases. Furthermore, the high velocities of the vehicles moving in a highway result in an increase in the frequency of cell boundary crossings. As a result, handover, defined as the mechanism that transfers an ongoing call from one cell to another as a user moves through the coverage area of the cellular system, will play a very important role in the design and the performance of the highway LAN. This report presents a general overview of handover mechanisms and proposes ways of applying handover on a highway LAN according to the network’s specific characteristics. In order to implement handover in a highway LAN, the modelling of the vehicle distribution and the radiowave propagation effects have been analyzed: The shifted negative exponential distribution can model both the spacing between the vehicles and the distance between the antenna of the base station and the nearest vehicle. The propagation environment is characterized by the path-loss attenuation, the Rice fading and the oxygen absorption (which has been ignored for the needs of this report). The phenomenon of shadowing has been neglected. A general overview of the handover mechanism, i.e. the goals of the handover procedure, performance metrics commonly used to evaluate handover algorithms, and the stages which constitute the procedure of handover, is presented. Handover mechanisms as applied in GSM and DECT have been investigated as examples of applied handover techniques. The issue of handover has not been addressed in the IEEE 802.11 and the HIPERLAN standards. Specific aspects of handover implied by the characteristics of the highway LAN have been examined. The propagation environment of a highway’s cell of 200 m. has been simulated using an exponential smoothing process. The averaging process has provided considerably accurate results and the crossover point can be adequately approximated. An absolute signal strength with velocity adjustable threshold algorithm is recommended for the handover decision procedure. The threshold levels are dynamically adjusted according to the velocity of each vehicle, that is, the higher the velocity of the vehicle is, the higher is the threshold value set. The Signal Prediction Priority Queuing (SPPQ) method is analyzed and proposed, in order to provide the optimum order in the execution of the handovers. A multicast-based handover scheme, known as sub-group buffering scheme, can be adopted in order to accomplish seamless communication service. Any numerical results obtained can not be used for the precise calculation of the parameters involved in the handover procedure, due to various arbitrary assumptions and simplifications. The propagation model still needs to be verified through actual measurements. However, the basic aspects of the handover mechanism have been extensively presented and the various approaches and proposed schemes could form the basis of the handover procedure to be implemented on a highway LAN.Electrical Engineering, Mathematics and Computer ScienceTelecommunicatie- en Verkeersbegeleidingssysteme
[[alternative]]The diversity and habitation of crabs in Lan-Yang River
No full text[[abstract]]ABSTRACT
The Lan-Yang River System occupies the whole Yi-Lan County, and the main river, Lan-Yang River, plays the significant role of the indicators of economy and environment in Lan-Yang plain. Yi-Lan River and Dong-Shan River join the River System by connecting with the mouth region of Lan-Yang River to develop an unique estuarine ecosystem.
In order to get more ecological information, the crab diversity survey was conducted from up-stream to down-stream of the Lan-Yang River; and the crab diversity and habitation in the tidal flat where the Dong-Shan River connected Lan-Yang River was set a site to study.
A total of seven families and twenty-eight species of crabs are found from the up-stream to down-stream of the Lan-Yang River; and four families and fourteen species in the tidal flat of the study site of the Dong-Shan River and Lan-Yang River connected area.
In the study of the habitation of crab community in the study site, data of three aspects has been collected during the high and low tide conditions and has been analyzed.
1. The material of substrate: samples analysis indicates that the substrate material is sand loam and doesn’t show much influence on seasonal changes and the tidal conditions.
2. Crabs sympatric relationship: the data confirms that five species: Uca arcuata, Uca borealis, Uca lactea, Tmethypocoelis ceratophora and Helice formosensis are dominant in daytime; two species: Chiromantes dehaani and Chiromantes haematocheir dominate in nighttime. In addition, it appears the different sympatric combinations in the high and low tide zones. And there is more diversity in the high tide zone.
3.The burrows：burrows in low tide zone are small, more in numbers and high density.
Overall, this study shows that the crab species distribution and the tidal conditions has close relationship, and this corresponds with hypothesis from predecessors.
The handedness of three dominant species of Fiddler Crabs: U. arcuata, U. borealis and U. lactea has been recorded. And the research shows that there is positive correlation of the side of major chela and burrow-emerging-entering.
Hope this study can provide a basis of ecological information of crabs for the further understanding about Lan-Yang River Ecology.
[[alternative]]To examine the strategies of National Alliance for rescuing Chi-lan Formosan Cedar Forest in Rescue Chi-lan Formosan Cedar Forest Movement by social marketing theory
No full text[[abstract]]The objectives of this reseach are to examine the strategies of National Alliance for Rescuing Chi-lan Formosan Cedar Forest(NARCFCF) in Rescue Chi-lan Formosan Cedar Forest Movement(RCFCFM) by social marketing theory, to understand its social marketing conditions, social marketing product objectives, social marketing strategies, and the control of social marketing plan. In the end, reseacher try to discuss whether RCFCFM was successful of not.
After analyzing the history of RCFCFM, motivate-general-public period in 1998 December was the key period of RCFCFM between 1998 July and 1999 April. Therefore the motivate-general-public period of RCFCFM is the period that this research try to discuss its social marketing strategies.
This research is aimed at figuring out the strategies of NARCFCF to stop the operations of collecting Formosan Cedar dead woods on Chi-lan Mountain, so it’s a case study. The research method of this study is mainly documentary analysis. Also, researcher interviewed the crews of NARCFCF. The documents of this research included meeting records, official documents, and news releases of NARCFCF, and newspaper reports.
The main goal of RCFCFM between 1998 July and 1999 April is to stop the operations of collecting Formosan Cedar dead woods on Chi-lan Mountain. The social product objective of motivate-general-public period of RCFCFM was making the whole general public to rescue Chi-lan Formosan Cedar Forest. NARCFCF hoped the general public could stand for RCFCFM by signing their names and attending actions to show the desire of the citizenry to rescue Chi-lan Formosan Cedar Forest in order to stop the operations of collecting Formosan Cedar dead woods on Chi-lan Mountain.
As far as the strategies of NARCFCF are concerned, when it comes to the target audience segment, NARCFCF adopted a mass marketing. When it comes to the marketing mix, the product was “Rescuing the most valuable Chi-lan Formosan Cedar Forest which can protect our life and which is the only left pure Formosan Cedar forest after years of lumbering”. After packaging its product appropriately and trying to reduce time inconvenience of the general public, NARCFCF used integrated marketing communication skills and distribution channels such as mass media, special media, and interpersonal communication.
As far as the control of social marketing plan is concerned, NARCFCF had meetings once a week in motivate-general-public period of RCFCFM to examine the progress of rescuing actions and adjust actions according to the new opportunities and threats.
From the contents of reports and articles on letters column of newspapers, and the general public and government respondences to RCFCFM, we can say that social markeitng outcome of motivate-general-public period of RCFCFM was good.
LAN management using computer graphics
No full textS.415-424Modern LAN (networks of workstations) are increasing in complexity due to the diversity of equipment being connected and the vaiety of services being offered. At the same time companies are placing more and more demands to maximize the efficiency of their personnel and the performance of their equipment. Despite the availability of computerized support tools, effective network management requires a high degree of operators alertness, coupled with the assimilation and mastery of vashor has investigated the use of computer graphics to agoals of network management systems are to reduce both network downtime and operating costs. In line with these goals, author has investigated the use of computer graphics to automate the diagnosis of LAN problems and LAN management. Knowledge-based tools and computer graphics can help operators to manage their networks more effectively and cope with the information overload inherently present in these demanding environments.31Nr.1/
Management realities - LAN for computer graphics and computer graphics for LAN
No full textS.3-15Modern LAN (networks of workstations) are increasing in complexity due to the diversity of equipment being connected and the vaiety of services being offered. At the same time companies are placing more and more demands to maximize the efficiency of their personnel and the performance of their equipment. Despite the availability of computerized support tools, effective network management requires a high degree of operators alertness, coupled with the assimilation and mastery of vast amounts of operation and maintenance knowledge. The goals of network management systems are to reduce both network downtime and operating costs. In line with these goals, author has investigated the use of computer graphics to automate the diagnosis of LAN problems and LAN management. Knowledge-based tools and computer graphics can help operators to manage their networks more effectively and cope with the information overload inherently present in these demanding environments
Công nghệ ATM và ứng dụng trong mạng cục bộ LAN
No full textIn this paper we present some selected important features of the Asynchronous Transfer Mode ATM and its application as backbone network technology used in Local Area Network LAN. Various standardized methods used to implement ATM-based LAN are mentioned. We consider the LAN Emulation according to ATM Forum in detail. The ATM-based network interconnection system COSY (Cell Oriented system) which the author was working for is illustrated as an example for implementing an ATM-based LAN
Performance Study of the IEEE 802.11 Wireless LAN Standard
No full textCurrently the IEEE is developing the 802.11 standard for a Physical and Medium Access Control (MAC) Layer protocol for a Wireless Local Area Network (LAN). This protocol employs two mechanisms for the medium access, a random access mechanism, called the Distributed Coordination Function (DCF), utilizing Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA) and an access mechanism, called the Point Coordination Function (PCF), which employs a polling list to grant stations access to the channel. In this thesis a performance study of the Wireless LAN protocol will be presented. The performance study is based on the application of several synthetic workload models. The Distributed Coordination Function is studied by the application of Poisson distributed data, FTP traffic and Mosaic traffic. The Point Coordination Function is studied by the application of a mix of voice traffic and Poisson distributed data traffic. The 802.11 protocol has been implemented in BONeS (Block Oriented Network Simulator). The results of a number simulations are presented for the two medium access mechanisms. Based on these results we will draw some conclusions and present recommendations for the improvement of the protocol.Applied SciencesElectrical EngineeringTelecommunications Grou
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