• 한국수자원학회:학술대회논문집
• /
• 한국수자원학회 2023년도 학술발표회
• /
• pp.34-34
• /
• 2023

The Chah-Nimeh reservoirs, which are a sort of natural lakes located in the border of Iran and Afghanistan, are the main drinking and agricultural water resources of Sistan arid region. Considering the occurrence of intense seasonal wind, locally known as levar wind, this study aims to explore the possibility to provide a TSM (Total Suspended Matter) monitoring model of Chah-Nimeh reservoirs using multi-temporal satellite images and in-situ wind speed data. The results show that a strong correlation between TSM concentration and wind speed are present. The developed empirical model indicated high performance in retrieving spatiotemporal distribution of the TSM concentration with R²=0.98 and RMSE=0.92g/m³. Following this observation, we also consider a machine learning-based model to predicts the average TSM using only wind speed. We connect our in-situ wind speed data to the TSM data generated from the inversion of multi-temporal satellite imagery to train a neural network based mode l(Wind2TSM-Net). Examining Wind2TSM-Net model indicates this model can retrieve the TSM accurately utilizing only wind speed (R²=0.88 and RMSE=1.97g/m³). Moreover, this results of this study show tha the TSM concentration can be estimated using only in situ wind speed data independent of the satellite images. Specifically, such model can supply a temporally persistent means of monitoring TSM that is not limited by the temporal resolution of imagery or the cloud cover problem in the optical remote sensing.

• 한국광학회지
• /
• 제35권4호
• /
• pp.170-174
• /
• 2024

대기 중 레이저 빔 전파 시 대기 난류에 의한 악영향을 해소하고 빔품질을 향상시키기 위해서 적응광학을 사용한다. 본 논문에서는 장거리 레이저 전송을 위한 적응광학계의 핵심 부품인 변형거울의 정밀 조립 방법을 제안한다. 변형거울은 거울판과 구동기, 플렉셔(flexure)로 구성되며 이 부품들을 정밀하게 조립하는 것이 성능을 좌우한다. 본 논문에서는 지그의 설계/제작을 통해 고밀집 다채널 실리콘-카바이드 변형거울을 완성했으며, 변형거울 성능 확인을 통해 제안한 방법의 유효성을 검증했다.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• 제12권2호
• /
• pp.786-799
• /
• 2018

Recently, NFV has attracted attention as a next-generation network virtualization technology for hardware -independent and efficient utilization of resources. NFV is a technology that not only virtualize computing, server, storage, network resources based on cloud computing but also connect Multi-Tenant of VNFs, a software network function. Therefore, it is possible to reduce the cost for constructing a physical network and to construct a logical network quickly by using NFV. However, in NFV, when a new VNF is added to a running Tenant, authentication between VNFs is not performed. Because of this problem, it is impossible to identify the presence of Fake-VNF in the tenant. Such a problem can cause an access from malicious attacker to one of VNFs in tenant as well as other VNFs in the tenant, disabling the NFV environment. In this paper, we propose Auto-configurable Security Mechanism in NFV including authentication between tenant-internal VNFs, and enforcement mechanism of security policy for traffic control between VNFs. This proposal not only authenticate identification of VNF when the VNF is registered, but also apply the security policy automatically to prevent malicious behavior in the tenant. Therefore, we can establish an independent communication channel for VNFs and guarantee a secure NFV environment.

• 제어로봇시스템학회논문지
• /
• 제8권4호
• /
• pp.303-307
• /
• 2002

Virtual hosting is a typical service to connect each directory of site and domain name. If traffic amounts may increase at one site present in the server, then it affects traffic amounts of other sites as well (including the sites which have flew requests). To overcome this problem, we suggest a simple feedback-control concept for the system by periodically monitoring the traffic and properly actuating traffic dispersions by investigating the log file. Specifically, large files are to be served in a backup server (to reduce the workload of the main server) by changing their own URL's in html format. In other words, it automatically redistributes the workload by using the URL. Furthermore, we also use the redirecting method by just adding html tags to html header. This method efficiently handles the workload and maintains the capability of the server effectively to the varying workload.

• 로봇학회논문지
• /
• 제8권3호
• /
• pp.186-196
• /
• 2013

Since its introduction (e.g., [4, 6]), virtual coupling technique has been de facto way to connect a haptic device with a virtual proxy for haptic rendering and control. However, because of the single dependence on spring-damper feedback action, this virtual coupling suffers from the degraded transparency particularly during contact tasks when large device/proxy-forces are involved. In this paper, we propose a novel virtual coupling technique, which, by utilizing passive decomposition, reduces device-proxy position deviation even during the contact tasks while also scaling down (or up) the apparent inertia of the coordinated device-proxy. By doing so, we can significantly improve transparency between multiple degree of freedom (possibly nonlinear) haptic device and virtual proxy. In other to use passive decomposition, disturbance observer of [3] is adopted to estimate human force with some dead-zone modification to avoid "winding-up" force estimation in the presence of device torque saturation. Some preliminary experimental results are also given to illustrate efficacy of the proposed technique.

• 한국통신학회논문지
• /
• 제27권5C호
• /
• pp.422-434
• /
• 2002

본 논문에서는 대용량 트래픽의 효율적 전송을 위해 B-DCS(Broadband-Digital Cross-connect System)망, 간선링, 지선링의 3계위 구조 광섬유 기간전송망을 제안하며 각 계위에서 경제적으로 망의 생존도를 보장하는 설계방법을 연구한다. 링 구축비용을 혼합정수계획(MIP) 모델을 이용해 수리적으로 최적화할 경우 비다항식 완전 문제(NP-complete problem)가 되어 실시간 내에 해를 구하기가 어려워지므로 본 논문에서는 B-DCS망을 위한 운용회선 및 예비회선의 최적할당 문제, 간선링을 위한 다중링 부하최적화 문제, 지선링을 위한 중첩링 부하최적화 문제에 대한 휴리스틱 알고리즘을 각각 개발하여 사례분석을 통해 그 효용성을 보인다.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• 제5권5호
• /
• pp.959-975
• /
• 2011

Wireless mesh networks enlarge the wireless coverage area by interconnecting relatively stationary wireless routers (mesh routers). As wireless mesh networks are envisioned to provide high-bandwidth broadband Internet service to a large community of users, the Internet gateway, which acts as a central point of Internet attachment for the mesh networks, is likely to suffer heavily from the scramble for shared wireless resources because of aggregated traffic toward the Internet. It causes performance decrement on end-to-end transmissions. We propose a scheme to balance the load in a mesh network based on link quality variation to different Internet gateways. Moreover, under the mesh coverage, mobile nodes can move around and connect to nearby mesh routers while still keeping the connections to the Internet through the best gateway in terms of link quality. In this structure, gateways perform the balancing procedure through wired links. Information about gateways and mobile node's location is distributed appropriately so that every mesh router can quickly recognize the best gateway as well as the positions of mobile nodes. This distributed information assists mobile nodes to perform fast handoff. Significant benefits are shown by the performance analysis.

• 한국생활과학회지
• /
• 제10권3호
• /
• pp.303-315
• /
• 2001

The purpose of this study is to evaluate the housing unit and investigate needs of housing in Home Economics curriculum of Home Economics teachers. The questionnaire survey was conducted 98 teachers participated in the minor training course in Chungbuk, August of 2000. When the teachers made their class in the section of housing, they emphasized respectively as the textual order: the space of housing and family life, the utilization of space, clean of residing circumstance in the middle school: and in the high school there was also concerned to the textual order: choice of housing, the house planning, interior design, maintenance of house. The teachers focused into the arrange of furniture and interior design for the students in the class, drawing of a plan in the contents of practical experience and performance. According to the survey results, the main point of class in housing should be emphasized the arranging of own room and function of other spaces in house for the students in the middle school. The high school curriculum should focus on the practical area to connect with the interior design. And in the section of housing it was needed to add the contents of management in the multi-family housing, housing problems, neighborhood environment for elderly, and also community planning.

• 한국정보통신학회:학술대회논문집
• /
• 한국정보통신학회 2013년도 춘계학술대회
• /
• pp.578-580
• /
• 2013

최근 스마트 디바이스의 증가에 따라 개인이 휴대하는 장치가 증가하고 있으며, 대부분의 스마트 디바이스에는 블루투스가 기본사양으로 탑재되고 있다. 그러나 블루투스 장치의 연결 제한으로 다중연결을 활용한 서비스 제공은 미흡한 상태이며, 다중연결이 가능하더라도 설정된 장치가 모두 접속되어야 데이터 통신이 가능한 문제점이 존재한다. 본 논문에서는 이러한 문제점을 해결하기 위한 방안으로 AT Command를 활용한 TDM(time division multiplexing) 방식의 다중연결 알고리즘을 제안하였다. 시뮬레이션을 통해 다수의 장치가 실시간 접속 및 데이터 전송이 가능하다는 것을 확인하였다.

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 2006년도 춘계학술대회 논문집
• /
• pp.189-190
• /
• 2006

A patient table considering x-ray transparency, mechanical safety and compact multi-axis moving mechanism has been developed. The goal of medical imaging technology is to keep radiation exposure of patients during x-raying to a minimum. In order to obtain clear pictures at low dose, however, the x-ray table which supports the patient must be sufficiently permeable to radiation to allow good image resolution. The table top is made of low density foam for x-ray transparent effective area and structural aluminum plate to connect moving mechanism under the table, covered with thin carbon fiber. This sandwich construction is very rigid and lightweight, so the table top can handle relatively heavy load comparing to its cantilevered structure which is unavoidable as long as cooperate with C-arm radiography. To verify the design results finite element static analysis and experimental tests have been done. According to the verification the results well satisfy certification guide lines as a medical device.