• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2002년도 하계학술대회 논문집 D
• /
• pp.2249-2251
• /
• 2002

CATV Network management system of korea is used for mainly monitor forward broadcasting signal because of the difficulty of tracking. measuring and control reverse path noise. Thereby purpose of design of the hardware is removing return path noise of CATV Network for maintaining two way network service of the highest quality. Return path management system is very effective in making CATV Network be the best media for ultra high speed data communication.

• 한국경영과학회지
• /
• 제39권2호
• /
• pp.97-109
• /
• 2014

This paper considers a reverse supply chain with simultaneous recovery of used products and manufacturing of brand-new ones. Recovered products are downgraded and have to be sold in a market different from that of brand-new products at a different price. In case of a shortage of recovered product inventory, a brand-new item, if available, can be offered at the price of a recovered product. In other words, one-way demand substitution is allowed. We address the joint decision of when to manufacture brand-new product, when to recover returned product, and how to control demand substitution to maximize the hybrid production system's profits. To this end, we propose a Markov decision Process model and investigate the structure of the optimal policy. Performance comparison is numerically implemented between the models with and without downward demand substitution option under different operating conditions of the system parameters.

• 한국통신학회논문지
• /
• 제15권1호
• /
• pp.71-79
• /
• 1990

逆바이어스 電壓變化에 따라 終端된 바랙터 리액턴스 變化로부터 發生되는 反射波의 連續的인 位相變化를 擴張시키기 위하여 인덕터와 바랙터를 直列로 連結시킨 回路와 하이브리드 링이 結合된 아나로그 移相器를 動作周波數 10GHz에서 設計하였으며, 分散特性 및 不連續 影響을 考慮하여 마이크로 스트립線路로 製作하였다. 實驗結果, 逆바이어스電壓을 20V가지 變化시킴에 따라 位相은 $52.34^{\circ}$에서 $235.01^{\circ}$까지 變化되므로서 $180^{\circ}$이상의 位相變化를 얻을 수 있었으며, 傳送 損失은 -3.6~14.3dB 및 Return loss는 -16~-18dB(1.37 < VSWR < 2.3)을 나타내었다.

• 한국군사과학기술학회지
• /
• 제15권3호
• /
• pp.250-256
• /
• 2012

Unmanned ground vehicles may be operated by remote control unit through the wireless communication or autonomously. However, the autonomous technology is still challenging and not perfectly developed. For some reason or other, the wireless communication is not always available. If wireless communication is abruptly disconnected, the UGV will be nothing but a lump of junk. What was worse, the UGV can be captured by enemy. This paper suggests a method, autonomous return technology with which the UGV can autonomously go back to a safer position along the reverse path. The suggested autonomous return technology for UGV is based on multi-correlated information based DB creation and matching. While SUGV moves by remote-control, the multi-correlated information based DB is created with the multi-sensor information; the absolute position of the trajectory is stored in DB if GPS is available and the hybrid MAP based on the fusion of VISION and LADAR is stored with the corresponding relative position if GPS is unavailable. In multi-correlated information based autonomous return, SUGV returns autonomously based on DB; SUGV returns along the trajectory based on GPS-based absolute position if GPS is available. Otherwise, the current position of SUGV is first estimated by the relative position using multi-sensor fusion followed by the matching between the query and DB. Then, the return path is created in MAP and SUGV returns automatically based on the MAP. Experimental results on the pre-built trajectory show the possibility of the successful autonomous return.

• 한국멀티미디어학회논문지
• /
• 제12권11호
• /
• pp.1671-1679
• /
• 2009

기존에는 제품의 원부자재 조달, 생산, 유통, 판매 등 기업과 고객을 연결하는 공급사슬관리의 대상이 순방향 물류(forward logistics)에 초점을 두어 왔으나, 그 범위가 역방향 물류(reverse logistics)로 확대되고 있다. 그러나 해외 선진기업들에 비해 국내 기업들의 역 공급사슬(reverse supply chain) 관리 능력은 강대적으로 저조한 수준에 머물러 있으며, 구체적으로 이를 수행할 수 있는 체계적인 인프라를 구축하고 있지 못한 실정이다. 이에 본 연구에서는 순방향 물류에 광범위하게 적용되고 있는 RFID 기술을 적용하여 포장, 보관, 하역, 운송 등 기존의 물류관리에 필요한 필수정보는 물론, 반품, 회수, 폐기, 재활용 등 친환경 공급사슬 관리를 수행하기 위한 정보를 제공하는 서비스 플랫폼을 개발하고자 하였다. 이를 위해 역방향 물류에 관한 문헌연구 및 선진사례를 분석하고, 국내외 추진현황을 검토하며 향후 적용되어야 할 역 공급사슬 관리를 위한 서비스 플랫폼을 제안한다.

• 한국주거학회논문집
• /
• 제13권6호
• /
• pp.89-99
• /
• 2002

The purpose of this research is to analyze the characteristics of flow rate distribution in hot-water piping networks in the apartment building. A 14-story apartment house was selected as a sample building and analyzed numerically by Hardy-Cross method. Two different piping networks, one has three vertical zones and the other of a single zone with automatic balancing valves, were compared. Some of research results are as follows; As the temperature of supply hot-water increases, the flow rate of it does by buoyancy effect, but this effect is not found in the piping network with automatic balancing valves. Non-uniformity in hot-water flow distributions to all stories in the piping system of single vertical zone can be completely reformed by the installation of either manually operated or automatic balancing valves in every story.

• Industrial Engineering and Management Systems
• /
• 제7권1호
• /
• pp.78-89
• /
• 2008

The need for holistic modeling efforts for returns that capture the extended closed loop supply chain (CLSC) system at strategic as well as operational level has been clearly recognized by the industry and academia. Strategic decision-makers need comprehensive models that can guide them in efficient decision-making to increase the profitability of the entire forward and return chain. Therefore, determination of a near optimal design configuration, which includes the environmental, economical and technological capability factors, is important in strategic decision-making effort that affect the profitability of the closed loop supply chain. In this paper, we adopted an improved system dynamics methodology to tackle strategic issues that affect various performance measures, like market, time/cost, environment etc., for closed loop supply chains. After studying real life implementation issues in CLSC design, we presented guidelines for the PBM (Participative Business Modeling) methodology and presented its extension for the strategic dynamic system modeling of return chains. Finally, we demonstrated the measurement of operational performance by extending SD (system dynamic) application to closed loop supply chain management.

• 한국콘텐츠학회논문지
• /
• 제20권6호
• /
• pp.439-444
• /
• 2020

이 연구는 자기공명영상검사 시 조영제 주입용으로 사용되는 자동주입기에서 조영제 역류에 의한 생리식염수의 오탁 현상을 방지할 수 있는 대안을 모색하고자 하였다. 연구방법은 실린지 내에서 조영제 역류를 차단할 대안으로 밸브를 자체 제작한 다음, 임상적용의 유용성을 알아보기 위해 생리식염수의 상태를 세 그룹으로 나누고 조영제 주입을 실험하여 각각 채취한 생리식염수의 지방소거 T1 강조영상으로 신호강도를 비교하였다. 연구결과, 그룹 1의 조영제 주입 전 생리식염수와 그룹 3의 역류방지용 밸브를 적용한 조영제 주입 후 생리식염수가 통계적으로 유의한 차이가 없었다(p>0.05). 이는 자체 제작한 역류방지용 밸브가 조영제 주입 시 생리식염수로 역류하는 조영제를 완벽히 차단한 것으로 분석된다. 결론적으로 조영제 자동주입기를 활용한 자기공명영상 동적검사 시 본 연구에서 제시한 역류방지밸브를 적용한다면 조영제 역류로 인한 생리식염수의 오탁 현상을 예방할 수 있으리라 본다.

• 대한산업공학회지
• /
• 제39권5호
• /
• pp.440-449
• /
• 2013

We consider a reverse supply chain with a production facility and a recovery facility, and address the joint control of production and disposal decisions for sustainable operations. Demands are satisfied from on-hand inventory of serviceable products, replenished via manufacturing or remanufacturing. Sold products may be returned after usage and each returned product is disposed of or accepted for recovery. Accepted returned products are converted into serviceable products after remanufacturing process. Formulating the model as a Markov decision process, we characterized the structure of the optimal production and disposal policy as two monotone switching curves under a special condition. Three types of heuristic policies are presented and their performance is numerically compared.

• 대한기계학회:학술대회논문집
• /
• 대한기계학회 2008년도 추계학술대회A
• /
• pp.1784-1787
• /
• 2008

Molecular dynamics (MD) simulations are used to analyze behavior of copper nanowires under cyclic loading. The embedded atom method (EAM) potential is employed to represent atomic interaction. Cyclic load is applied in two ways (Forward Tension / Reverse Compression and Forward Compression / Reverse Tension). The results show that dislocations are piled up as a result of plastic deformation during alternate tensile and compressive loading. After cyclic loading with a change of direction, yield stress decreases in consequence of the effect by the dislocation pileups. On the other hand, under FC/RT cyclic load, phase transformation represent associated with mechanical twinning. And copper nanowire can return to almost former undeformed condition during tensile loading at 300K.