• Title/Summary/Keyword: 가변성

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A Parametric Study of Pulsed Gamma-ray Detectors Based on Si Epi-Wafer (실리콘 에피-웨이퍼 기반의 펄스감마선 검출센서 최적화 연구)

  • Lee, Nam-Ho;Hwang, Young-Gwan;Jeong, Sang-Hun;Kim, Jong-Yeol;Cho, Young
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.18 no.7
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    • pp.1777-1783
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    • 2014
  • In this paper, we designed and fabricated a high-speed semiconductor sensor for use in power control devices and analyzed the characteristics with pulsed radiation tests. At first, radiation sensitive circular Si PIN diodes with various diameters(0.1 mm ~5.0 mm) were designed and fabricated using Si epitaxial wafer, which has a $42{\mu}m$ thick intrinsic layer. The reverse leakage current of the diode with a radius of 2 mm at a reverse bias of 30 V was about 20.4 nA. To investigate the characteristic responses of the developed diodes, the pulsed gamma-radiation tests were performed with the intensity of 4.88E8 rad(Si)/sec. From the test results showing that the output currents and the rising speeds have a linear relationship with the area of the sensors, we decided that the optimal condition took place at a 2 mm diameter. Next, for the selected 2 mm diodes, dose rate tests with a range of 2.47E8 rad(Si)/sec to 6.21E8 rad(Si)/sec were performed. From the results, which showed linear characteristics with the radiation intensity, a large amount of photocurrent over 60mA, and a high speed response under 350ns without saturation, we can conclude that the our developed PIN diode can be a good candidate for the sensor of power control devices.

Performance Improvement of an Energy Efficient Cluster Management Based on Autonomous Learning (자율학습기반의 에너지 효율적인 클러스터 관리에서의 성능 개선)

  • Cho, Sungchul;Chung, Kyusik
    • KIPS Transactions on Computer and Communication Systems
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    • v.4 no.11
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    • pp.369-382
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    • 2015
  • Energy aware server clusters aim to reduce power consumption at maximum while keeping QoS(quality of service) compared to energy non-aware server clusters. They adjust the power mode of each server in a fixed or variable time interval to activate only the minimum number of servers needed to handle current user requests. Previous studies on energy aware server cluster put efforts to reduce power consumption or heat dissipation, but they do not consider energy efficiency well. In this paper, we propose an energy efficient cluster management method to improve not only performance per watt but also QoS of the existing server power mode control method based on autonomous learning. Our proposed method is to adjust server power mode based on a hybrid approach of autonomous learning method with multi level thresholds and power consumption prediction method. Autonomous learning method with multi level thresholds is applied under normal load situation whereas power consumption prediction method is applied under abnormal load situation. The decision on whether current load is normal or abnormal depends on the ratio of the number of current user requests over the average number of user requests during recent past few minutes. Also, a dynamic shutdown method is additionally applied to shorten the time delay to make servers off. We performed experiments with a cluster of 16 servers using three different kinds of load patterns. The multi-threshold based learning method with prediction and dynamic shutdown shows the best result in terms of normalized QoS and performance per watt (valid responses). For banking load pattern, real load pattern, and virtual load pattern, the numbers of good response per watt in the proposed method increase by 1.66%, 2.9% and 3.84%, respectively, whereas QoS in the proposed method increase by 0.45%, 1.33% and 8.82%, respectively, compared to those in the existing autonomous learning method with single level threshold.

Synthesis of Renewable Resource-derived Furan-based Epoxy Compounds and Their Adhesive Property (재생자원 유래 퓨란계 에폭시 화합물의 합성 및 접착 특성)

  • Lee, Jae-Soung;Lee, Sang-Hyeup;Jeong, Jaewon;Kim, Baekjin;Cho, Jin Ku;Kim, Hyun Joong
    • Journal of Adhesion and Interface
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    • v.11 no.2
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    • pp.41-49
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    • 2010
  • Furan-containing epoxide monomers (8, 9) were designed and synthesized as carbon-neutral, environment-friendly adhesion material. Bicyclic skeleton were constructed using the Diels-Alder reaction of furan and methyl acrylate, both readily accessible starting material from a biomass via bio-refinery process. After reduction of ester functionality, resulting hydroxyl moieties were coupled to epichlorohydrin to provide the epoxy-functionalized furanic monomers (8, 9). The structure of new furanic monomers was confirmed by $^1H$ and $^{13}C$ NMR spectroscopy. As UV-curable monomers, basic properties such as UV curing time and the extent of UV curing were evaluated by photo DSC. Photo-curing shrinkages were measured by linear variable differential transformer transducer (LVDT) and the effect of molecular structure on shrinkage was considered. In addition, new synthetic compounds showed the shear strength over 3 MPa when they were photo-cured between polycarbonate plates, which indicates these compounds are feasible to use as photo-curable adhesive materials.

A Construction safety management system based on Building Information Modeling and Real-time Locating System (위치추적기술을 이용한 BIM기반 건설현장 안전관리 시스템)

  • Lee, Hyun-Soo;Lee, Kwang-Pyo;Park, Moon-Seo;Kim, Hyun-Soo;Lee, Sa-Bum
    • Korean Journal of Construction Engineering and Management
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    • v.10 no.6
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    • pp.135-145
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    • 2009
  • The main goal of construction projects from the past has been enhancing efficiency by reducing cost and time. but, seeing the current condition of safety management of many construction companies nowadays, it is true that not much attention has been paid to safety management for a long time. However, there are paradigm shift from the cost and term of works to safety management in the construction industry, from this circumstance the safety management is evaluated more importantly. Though less accident happens compared to past, the accidents are getting greater because construction projects nowadays are bigger and more complex and monetary loss from the accidents are increasing. Also, the severity is getting greater and even fatal. For this reason, more improved safety management is very necessary. Therefore, we are to propose more efficient system for safety management in this thesis. Technical parts for developing system include many technique such as Real Time Locating system, and other techniques like Monitoring module based on BIM, Data Mart, Alarm are also applied together. Through this system, in the construction site, safety management is performed more effectively and widely because the system can manage the human resource and fluid situation. Also, safety manager can conduct more systematically and advanced safety management through human resource dominated safety management.

Batching delivery for VCR-like functions in video-on-demand service system (주문형 비디오 서비스 시스템에서 VCR 기능을 위한 Batching 전송)

  • 박호균;유황빈
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.22 no.12
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    • pp.2852-2859
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    • 1997
  • Video-On-Demand system provides electronic video rental services from remote video servers on a broadband communication networks. Most of proposed VOD systems are typically designed for one-to-one conncetion between a user and video server. Therefore, video server stream services to customers individually by allocating a dedicated transmission channel and a set of video server resources for each customer. However, it is inefficiency and wxpensive way when server support multiple users who access the same video stream with a dedicated video channel. Therefore, to achieve cost-effectiveness, batching have studied method that uses multicast communication to simultaneously service all users requesting the same video with a single video with a single video stream. However, the application of the multicast communication by batching detract from the VCR-like function and on-demand nature of the system. In this paepr, we propose a scheme that can support an interactive VCR for all user requesting the same video stream with batching. To reduce a server I/O and network bandwidth requirement, dynamic buffer is allocated to access node which has variable playout poit. Consequently, it makes possible interactive VCR operation as if customer uses true VOD system. Also, this scheme can just deliver a multicast stream without delay after an initial request or VCR action occurred. The policy can guarantee acceptable services to number of users at minimum cost.

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A Development of Design database structure and Database Application System applicable for design Foundation Courses. (디자인 데이터베이스 체계구축 및 운용시스템 개발에 관한 연구 -기초조형교육을 중심으로-)

  • 이종호
    • Archives of design research
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    • v.12 no.4
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    • pp.283-292
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    • 1999
  • As network and multimedia service has increased in educational environment, it is needed to study on digital system based educational scenarios, especially in art and design departments in which visual educational materials mainly used. Therefore, this study was conducted with three objectives: first, developing components of design database and their classification system, second, developing contents of database for fundamental form education in design, and third, developing application method of database. According to these objectives, the secondary research was implemented into two directions; the analysis of classification categories of design, and the analysis of contents and process of fundamental form design education. From the secondary research, it was found that design database should have a flexible structure with flexible components as well as fixed components to include subjective and aesthetic assessment. In the end, the application methods and user interface system of design database was developed based on design educational scenarios.

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Development of Screening Technology for Marine Waste Disposal (수산폐기물 전처리 용 스크린기술 개발)

  • Moon, Serng-Bae;Jun, Seung-Hwan;Jin, Gang-Gyoo
    • Journal of Navigation and Port Research
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    • v.33 no.1
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    • pp.57-63
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    • 2009
  • In order to effectively isolate the marine wastes with an effluent standard, the pretreatment process is required to isolate solid materials from the liquid-solid mixed wastes. The more effective the pretreatment becomes, the more processing capacity of posttreatment will be improved and process facilities will be downsized. In this paper, we suggested the vibrating reverse-slant screen, investigated the optimal vibration frequency and vibrator installation angle for the separation of the liquid solid mixed wastes. Several experiments for separation efficiency were conducted under the condition of various vibration frequency($35{\sim}60Hz$, 5Hz interval) and vibrator angle($0^{\circ}$, $30^{\circ}$, $45^{\circ}$, $90^{\circ}$) considering the crack of screen. The screen inclination angle is set up the gradient as $3^{\circ}{\sim}5^{\circ}$ through the preliminary experiments. Also, we made two types of screen(respectively rectangle and square screen). The separation device has shown the optimum efficiency at vibrator angle $0^{\circ}$ and vibration frequency 60Hz, and has no relation with the shape of screen. And the proposed technology is verified by comparing with quantity of suspended solids before and after filtration.

Development of Continuous Rainfall-Runoff Model for Flood Forecasting on the Large-Scale Basin (대유역 홍수예측을 위한 연속형 강우-유출모형 개발)

  • Bae, Deg-Hyo;Lee, Byong-Ju
    • Journal of Korea Water Resources Association
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    • v.44 no.1
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    • pp.51-64
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    • 2011
  • The objective of this study is to develop a continuous rainfall-runoff model for flood prediction on a large-scale basin. For this study, the hourly surface runoff estimation method based on the variable retention parameter and runoff curve number is developed. This model is composed that the soil moisture to continuous rainfall can be simulated with applying the hydrologic components to the continuous equation for soil moisture. The runoff can be simulated by linking the hydrologic components with the storage function model continuously. The runoff simulation to large basins can be performed by using channel storage function model. Nakdong river basin is selected as the study area. The model accuracy is evaluated at the 8 measurement sites during flood season in 2006 (calibration period) and 2007~2008 (verification period). The calibrated model simulations are well fitted to the observations. Nash and Sutcliffe model efficiencies in the calibration and verification periods exist in the range of 0.81 to 0.95 and 0.70 to 0.94, respectively. The behavior of soil moisture depending on the rainfall and the annual loadings of simulated hydrologic components are rational. From this results, continuous rainfall-runoff model developed in this study can be used to predict the discharge on large basins.

A Study on Variable Speed Limit Strategies in Freeway Work Zone Using Multi-Criteria Decision Making Process (다기준 의사결정기반 고속도로 공사구간 VSL전략에 관한 연구)

  • Park, Juneyoung;Oh, Cheol;Chang, Myungsoon
    • Journal of Korean Society of Transportation
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    • v.31 no.5
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    • pp.3-15
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    • 2013
  • The purpose of this study is to propose a methodology for operating variable speed limit (VSL) strategies in freeway work zones. A notable feature in this study is to incorporate a multi-criteria decision making process into deriving better VSL strategies. Decision criteria in this study include operational efficiency, safety, and environmental impacts. Travel speed, acceleration noise, and CO2 were used as performance measures for evaluating VSL strategies. A multi-criteria value function was developed through an analytical hierarchical process (AHP) for representing expert's knowledge. Then, a variety of VSL operations scenarios were investigated utilizing a microscopic traffic simulation suite, VISSIM. The proposed methodology would be useful in supporting more efficient, safer, and more environment-friendly traffic operations and control in freeway work zones.

Gesture Spotting by Web-Camera in Arbitrary Two Positions and Fuzzy Garbage Model (임의 두 지점의 웹 카메라와 퍼지 가비지 모델을 이용한 사용자의 의미 있는 동작 검출)

  • Yang, Seung-Eun
    • KIPS Transactions on Software and Data Engineering
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    • v.1 no.2
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    • pp.127-136
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    • 2012
  • Many research of hand gesture recognition based on vision system have been conducted which enable user operate various electronic devices more easily. 3D position calculation and meaningful gesture classification from similar gestures should be executed to recognize hand gesture accurately. A simple and cost effective method of 3D position calculation and gesture spotting (a task to recognize meaningful gesture from other similar meaningless gestures) is described in this paper. 3D position is achieved by calculation of two cameras relative position through pan/tilt module and a marker regardless with the placed position. Fuzzy garbage model is proposed to provide a variable reference value to decide whether the user gesture is the command gesture or not. The reference is achieved from fuzzy command gesture model and fuzzy garbage model which returns the score that shows the degree of belonging to command gesture and garbage gesture respectively. Two-stage user adaptation is proposed that off-line (batch) adaptation for inter-personal difference and on-line (incremental) adaptation for intra-difference to enhance the performance. Experiment is conducted for 5 different users. The recognition rate of command (discriminate command gesture) is more than 95% when only one command like meaningless gesture exists and more than 85% when the command is mixed with many other similar gestures.