• 제목/요약/키워드: VMI

검색결과 62건 처리시간 0.022초

아토초 펄스의 전자 검출 장치 개발

  • 이윤만;김경록;안병남
    • 한국진공학회:학술대회논문집
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    • 한국진공학회 2012년도 제43회 하계 정기 학술대회 초록집
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    • pp.209-209
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    • 2012
  • 전자의 에너지를 측정하기 위한 분석장치는 원자핵물리뿐만 아니라 화학과 생물학 등 다양한 분야에 걸쳐 매우 유용하게 사용될 수가 있다. 특히 최근에 극고속 과학과 관련해서 매우 짧은 펄스인 아토초 펄스의 발생에 대한 특성평가를 위해 매우 중요한 장치로 사용되고 있다. 그 중 VMI (Velocity Map Imaging) 방법은 TOF (Time of Flight) 방법과 유사하지만, CCD 카메라를 추가로 사용하여 이차원 이미지를 얻음으로써 전자의 운동에너지 및 각도 분포에 대한 정보를 얻을 수 있고 또한 전극에 인가되는 전압은 TOF와 달리 매우 높다. 이번 개발에서는 기존의 전극 렌즈의 geometry와 비교해서 VMI Spectrometer 전극 렌즈의 수를 늘려 multi-electrode concept을 도입함으로써 높은 운동에너지(~1000 eV)를 가진 전자들을 MCP detector상에서 imaging 하는데 있어 높은 공간 분해능(resolution)을 갖도록 설계하고, 또한 높은 사양의 MCP detector 및 CCD 카메라를 이용하여 시간 분해능을 높임으로써 아토초 펄스를 이용한 극고속 실험에 이용 가능하도록 제작하였다.

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Lightweight Intrusion Detection of Rootkit with VMI-Based Driver Separation Mechanism

  • Cui, Chaoyuan;Wu, Yun;Li, Yonggang;Sun, Bingyu
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • 제11권3호
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    • pp.1722-1741
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    • 2017
  • Intrusion detection techniques based on virtual machine introspection (VMI) provide high temper-resistance in comparison with traditional in-host anti-virus tools. However, the presence of semantic gap also leads to the performance and compatibility problems. In order to map raw bits of hardware to meaningful information of virtual machine, detailed knowledge of different guest OS is required. In this work, we present VDSM, a lightweight and general approach based on driver separation mechanism: divide semantic view reconstruction into online driver of view generation and offline driver of semantics extraction. We have developed a prototype of VDSM and used it to do intrusion detection on 13 operation systems. The evaluation results show VDSM is effective and practical with a small performance overhead.

정보기술을 활용한 공급 사슬의 협업적 조달 시스템에 관한 연구 (Collaborative Procurement System for IT-Enhanced Supply Chains)

  • Eungab Kim;Chankwon Park;Kitae Shin
    • 한국전자거래학회지
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    • 제7권2호
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    • pp.129-141
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    • 2002
  • This paper deals with the collaborative procurement process in a two-echelon supply chain that a manufacturing company and a contractor are connected through the information system. The real time information about inventory and production processing becomes available through this information system. We raise two issues related to the collaborative procurement process. First, we propose a VMI(Vendor-Managed Inventory) type of the procurement policy which focuses on the cost minimization for the total supply chain rather than individual companies. Second, based on the simulation study, we demonstrate that a collaborative procurement process is more cost-effective over classical procurement processes such as (Q, r). The result obtained in this paper can be applied to the quantitative evaluation of the cost saving effect when companies build the information sharing based, collaborative procurement system.

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Simulation Study of Two Supply Chain Collaboration Programs: Consignment and VMI

  • Ryu, Chung-Suk
    • 유통과학연구
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    • 제14권4호
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    • pp.21-31
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    • 2016
  • Purpose - This study examines how consignment and Vendor-Managed Inventory perform as supply chain collaboration programs. By using three key collaborative features, this study defines the collaboration programs and develops theoretical models of different supply chain systems. Research design, data and methodology - This study conducts sophisticated analysis on the supply chain systems by applying simulation modeling based on time-phased operations. The simulation model represents a two-stage supply chain system where a supplier sells a single item to a buyer, and it incorporates various operations. Results - In general, the simulation outcomes support that more advanced collaboration programs outperform less advanced ones. The analysis on the simulation outcomes identifies the significant value of information sharing in both collaboration programs. The specific conditions where the particular collaboration system outperforms the others are recognized. Conclusions - The outcome of this study supports that the supply chain system can improve its performance by having more collaborative features. This study provides business practitioners with guidelines to identify the circumstances that the specific collaboration program can fully exploit its advantages.

소매점 공급사슬에서 공급자주도 재고/분배 문제를 위한 발견적 해석 (A Heuristic for Vendor-managed Inventory/Distribution Problems in the Retail Supply Chain)

  • 홍성철;박양병
    • 경영과학
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    • 제25권1호
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    • pp.107-121
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    • 2008
  • As to more efficiently manage the inventory in the retail supply chain and to meet the customer demand in a timely manner, vendor-managed inventory (VMI) has been widely accepted, which manages inventory in the retail supply chain via sharing information and collaborating with the retailers. Applying VMI generates vendor-managed inventory/distribution problem (VMIDP), which involves inventory management for both the vendor and the retailers, and the design of vehicle routes for delivery, to minimize the total operating cost in the supply chain. In this paper, we suggest a mixed integer programming (MIP) model to obtain the optimal solution for VMIDP in a two-echelon retail supply chain, and develop an efficient heuristic based on the operating principles of the MIP model. To evaluate the performance of the heuristic, its solution was compared with the one of the MIP model on a total of twenty seven test problems. As a result, the heuristic found optimal solutions on seven problems in a significantly reduced time, and generated a 4.3% error rate of total cost in average for all problems. The heuristic is applied to the case problem of the local famous franchise company together with GIS, showing that it is capable of providing a solution efficiently in a relatively short time even in the real world situation.

대형할인매장의 VMI 시스템을 위한 효율적인 재고관리 시스템 (Efficient Deterministic Inventory System in VMI System of the Discount Retailer)

  • 백시현;방인홍;김내헌
    • 한국경영과학회:학술대회논문집
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    • 대한산업공학회/한국경영과학회 2000년도 춘계공동학술대회 논문집
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    • pp.139-142
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    • 2000
  • Excessive inventories result from poor scheduling, planning, and controls, and the converse is also same. With adequate inventories, supplies can transport products to customers in time without excessive delivering cost. So efficient inventory control is vital for successful logistics management operation. In terms of mass discount retailers such as Wal-Mart, Carrefour, E-Mart, and so on, they require the high-quality services such as a small-amount and a high-frequency delivery because of having small warehouse and wanting possess much more various goods. In the opposite, manufactures ask mass discount retailer to delivery more lots of goods because of reducing the number of deliveries. It goes without saying that both wish to prevent stockout(lack of inventories). Usually, mass discount retailers have the power more than manufactures. This paper proposed how to manage inventory and how many to order in view of the TPLC and supplier. We considered the economic order quantity models for multiple items so as to prevent urgent deliveries as possible as. And the tradeoff stockout costs and delivering costs.

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