802.11e 매체접근제어 프로토콜에서 트래픽의 발생률에 따른 EDCF의 종단간 전달 지연 특성 연구

변태영,조무호 경주대학교 정보전자기술연구소 2003 情報電子技術論叢 Vol.2 No.-

In this paper, we analyze the end-to-end path delay in the EDCF mode of 80211e network which provide QoS control capability in the wireless LAN environment. As described in 80211e specification, under the EDCF operation, the realtime traffic such as streaming service, VoD service with high priority get more frequent chance to transmit frames than that of low priority traffic. To verify these characteristic, we implemented a simulation tool which support the 80211e MAC and measured the characteristics of the end-to-end path delay among various traffic streams. The simulation results showed that the delay of traffic with high priority is supported with a QoS guarantee, but the traffic with low priority experience a great delay as the number of mobile terminal is above a point which is regarded as threshold.

유기화합물과 불균일 혼합물 처리를 위한 인공화학실험실의 확장

변영태,조성태 弘益大學校 科學技術硏究所 1998 科學技術硏究論文集 Vol.9 No.1

Experiments in a laboratory are very important in science education for primary, middle, and high school students. However, education systems in many countries do not provide enough experiment chances to students for several reasons. One of most important reasons is hat financial support from a government is not sufficient. Besides that, insufficiency of experimental and managerial facilities for laboratories and equipments, danger of experimental accidents, heavy pressure to get high scores of entrance written exams for a school of higher grade, and other difficulties would make it so. From desirable science education's point of view, there is still a problem in countries where students have reasonable experimental chances. The problem is that every student does not participate equally in experiments and they do only predetermined experiments during class hours. Nobody can do any experiment, which is not predetermined,whenever they want. As an alternative to solve the problem, we developed ACL (Artificial Chemistry Laboratory) to make students do on personal computers any experiment whenever they want. However, the previous ACL system has limitations, since it covers only pure substances and homogeneous mixtures. ACL-V is an extended version of the previous ACL system in order to cover organic (carbonic) compounds and heterogeneous mixtures. To include heterogeneous mixtures, we extend the knowledge base, the spatial description lanaguage, the existence shape description langauge, and related processes. ACL-V handles solid, liquid, and gas heterogeenous mixtures. To include organic (carbonic) compounds, we extend the knowledge base and the process libraray. The hierarchy of the knowledge base is made based on the commonly accepted grouping knowledge of chemistry. The first subclass of the Carbonic class is the Aliphatic class for aliphatic carbonic material. It is further divided into three subclasses. The Aromatic class is for aromatic carbonic material and divided into several subclasses, and the HighMolecu

MFCM을 사용한 모델 기반의 진단 시스템

卞永泰 弘益大學校 科學技術硏究所 1994 科學技術硏究論文集 Vol.5 No.-

This paper describes a diagnostic system which has deep knowledge such as a mental model and commonsense knowledge. while traditional knowledge-base systems use shallow knowledge. We implement MFCM(Most Fuzzy Cognitive Map) and its simulation algorithm for a model-based system which allows us to represent, inference and understand behaviors of physical devices or systems, and develop a diagnostic system using the model and causal constraints. When a variable in a system is known to be wrong, the adjacency principle selects a possible constraint which affects the variable value, and then the constraint suspension strategy is used to build a fault model based on the original model. The diagnostic system uses the same simulation algorithm and therefore generates a state which describes the current wrong behavior. With a single fault assumption, the current implementation identifies which constraint(i.e. which part of a physical system) works wrong.

인공과학실험실 확장 : 전기 실험

변영태,오석일 弘益大學校 科學技術硏究所 2000 科學技術硏究論文集 Vol.11 No.-

ASL-EE (Artificial Science Laboratory for Electrical Experiments) is founded on the system structure of ACL-V (Artificial Chemistry Laboratory-V), which is formerly formulated and based on hierarchical knowledge related chemistry. ASL-EE has been improved and developed as a virtual experimental system that can simulate basic direct current circuit experiments, magnetic field experiments concerning magnetic force, and chemical cell experiments using the knowledge of chemistry that enclosed to elementary, middle, and high school curriculums. The former inference model had been improved and modified so that each consisting electronic device plays a role as a center of the main analyzing principal in a circuit. We expand this system to make more various experiments; not only the direct current experiments but also alternating current circuit is possible. The results show the possibility of contribution for science education by allowing students to do non-predefined electrical experiments in WYSIWYG(What You See Is What You Get) environment on computers. In this paper, we present an integrated strategy of partitioning and scheduling. We apply FDS technique for the scheduling. But, we use the relative scheduling urgency for partitioning that is the effect of an assignment of a node to a specific time step. The proposed algorithm produced good results and better execution time than paper [14]'s results for all benchmarks. In the future, we should include the communication costs between hardware and software components.

웹에서의 제품정보 수집 정보에이젼트

卞永泰,吳錫一 弘益大學校 科學技術硏究所 2001 科學技術硏究論文集 Vol.12 No.-

ASL-EE(Artificial Science Laboratory for Electical Experiments) has been developed as a virtual experimental system that can simulate basic direct current circuit experiments, magnetic field experiments concerning magnetic force, and chemical cell experiments using the knowledge of chemistry that enclosed to elementary, middle, and high school curriculums. Since the Web provides a lot of useful information about electrical components as well as general products, it is desirable to give ASL-EE users chances to look at commercial information about electrical components so that when they want to buy some of components used in the simulation in ASL-EE, they can get useful product information about the components before buying. This paper introduces WIMA-EE(Web Information Mining Agent for Electrical Elements) which consists of three modules: Collector, Extractor, and Wrapper. Collector collects related Web pages by using Web Robot, and Extractor extracts electrical component part numbers from tables on Web pages by tag-based analysis. Wrapper is a program which generates part numbers automatically based on the information of Extractor, sends them to related shopping malls and get product information when the results are successful. The current system covers only semi-structured (table form) Web pages and should be extended in future.

자연과학(동물) 정보에이전트의 설계 및 구현

변영태,오정민 弘益大學校 科學技術硏究所 1999 科學技術硏究論文集 Vol.10 No.1

Information providers of internet are increased by the fast technical development of network, and they provide a vast amount of information in various fields. Because of this reason, it becomes too hard for users to get fast what they want. There are several search engines that help users with the keyword matching method, but it is still a burden to users to find suitable keywords. Therefore we implement the intelligent information retrieval agent(HILA-la : HongIk Information Agent) that converts user's queries to forms to be compatible to user's thought and suitable to a specific domain, and provides the necessary information. The knowledge base about an animals domain has been built in an ontological aspect to share information between information agents and the HILA-la system supplies necessary information by processing the queries of users and other agents, and also shows URL list of proper web pages by extending given queries based on knowledge base. We also supplement new operators for users to represent their thought more clearly and make the system behave more intelligent by learning from accumulated results and user feedback. HILA-la has been developed on Windows 98 with Visual C++ 5.0, CLIPS and MS Access, the results are promising in terms of the information provider.

조직공정성의 개념 및 조직시민행동과의 관계에 대한 이론적 고찰

안관영,변태수 尙志大學校産業經營硏究所 2002 産業經營硏究 Vol.12 No.-

This study is based on the customer's satisfaction and emphasizes the high class service and the importance of personal service-quality according to the customer's visiting for the hotel accomodations located at chun-cheon city area. Service environment quality has become one of major factors in the selection of various purchase decisions, In fact, the level of a server's service quality affects the hotel firm's performance and the server's quality is emphasized not only as key determinants of the customer's satisfaction but also as complements of the server's strategic variables. This study focuses attention on the need of guests and some changes affect resort hotel companied only at an individual level. Hotel industry should be changed to promote diffusion of innovations or the spread of new ideas or hotel service products for behavioral characteristics of the consumers visiting Chun-cheon area. In addition, they should conduct occasional consumer decision surveys to monitor their standing with guests.

토지 관리를 위한 토지 정보시스템의 응용에 관한 연구

윤영훈,변무룡,김응남,백종원,양인태 江原大學校 産業技術硏究所 1991 産業技術硏究 Vol.11 No.-

This study is concerned with the effective of aspects of utility management and land management, the accuracy of data, the structure of cross reference file of data and the perpetial preservation of data management through a drawing of computer and database, when land and utility information of the application of Land Information System is made on the computer. It will be shown that the present system of land management is inadequate in various contexts and occure in difficult problems of use, as presented in this paper, computer alternative to these difficulties is efficiently managed and conveniently used land utility management. The ultimate goal is provided the necessary information of various areas as the presented land management operation is builted a drawing of computer and database construction through the computer.

비침습적 검사를 이용한 수술후 하지 심부 정맥 혈전증의 감시

김영욱,정한준,윤봉호,김신윤,이상국,변경환,김태헌 경북대학교 병원 1997 경북대학교병원의학연구소논문집 Vol.1 No.1

Deep vein thrombosis is recognized as a common complication in surgical patients in western countries especially in patients with high risk factors. The purposes of this study were to detect leg DVTs in early postoperative period by non-invasive surveillance and to analyze the risk factors of DVT. One hundred seventy one patients who underwent major operations(67 curative resection of colorectal cancer, 64 total hip replacement, 38 femur operation for fracture, and 2 colon resections for benign colon disease) were included for the prospective surveillance of leg DVT within 2 weeks after the operations. For the surveillance of leg DVT, strain gauge plethysmography(SPG) and Duplex scanning of both legs were completed for all patients except 10 patients. These 10 patients were examined in only one leg. The patients with past history of leg DVT or under prophylactic anticoagulant therapy were excluded from this study. To determine the risk factors related with leg DVT formation, age and sex of the patients, indication of surgery or surgical procedures, duration of operation, position during the operation, duration of postoperative immobilization, and preoperative serum level of antithrombin III (AT- III) were analyzed using Chi-square test. After performing SPG of 342 legs, 38 legs, showed abnormal on venous outflow/venous capacitance discriminant line chart, and 13 legs of 12 patients showed the finding(s) suggesting DVT on duplex scanning. Among the patients with abnormal duplex findings, 7 limbs(53.8%) were symptomatic, but the remaining 6 legs were silent. In 6 (15.8%) patients of 36 femur operations, 3(4.7%) of 64 total hip replacements and 3(4.5%) of 67 curative resections of colorectal cancer developed DVT by duplex scanning in the iliac(5), femoral-popliteal(6), and isolated calf(2) veins. After analyzing the risk factors, we could not find any statistically significant(p<0.05) factor related with leg DVT.

비만 여성을 대상으로 한 해조류 추출물의 국부처치와 운동 병행을 통한 지방분해 효과의 임상적 검정

서태수,이인숙,변재철,김규호,박승한,김유영,김상국,김현정,김상기,신동철,성미영,박종석,김종기,박언휘 한국스포츠리서치 2003 한국 스포츠 리서치 Vol.14 No.3

This study was carried out to test the body fat breakdown during topical seaweed extract treatment and in combination with the aerobic exercise. Of 20 female obesity subjects, ten treated a cream types of seaweed extract(control group) and ten treated a placebo cream(placebo group). Topical treatment of each sample was designed for 4 weeks, and treated with 2 times a day about 10ml on the abdomen and the thigh, respectively. All subjects were participated aerobic dance half hour a day and four times a week. After 4 weeks of topical treatment and exercise, they were measured body fat, skinfold thickness, body circumference. Then venous blood samples were taken and analyzed blood cells, serum enzymes, and serum lipids. There were reduction of body weight, % of body fat, antebrachium, brachium, chest, waist, thigh circumference and abdomen thickness between pre and post treatment in both group. Especially, body weight and % of body fat significantly reduced in the subjects treating the seaweed extract than those treating the placebo. There were significant decrement in total cholesterol and LDL whereas increment in HDL and TBIL in the control group, but no significant difference in the placebo group. In conclusion, there were 7.6% of body fat reduction during 4 weeks of aerobic exercise and 21% of body fat reducement in combination of topical seaweed treatment and exercise, respectively. These results suggest that the topical treatment of seaweed extract should be very effective for fat breakdown. Especially, the body fat breakdown maximized in the combination with the topical seaweed extracts treatment and the aerobic exercise.