• Journal of Information Processing Systems
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• v.13 no.3
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• pp.476-490
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• 2017

In the centralized cloud controlled environment, the decision-making and monitoring play crucial role where in the host controller (HC) manages the resources across hosts in data center (DC). HC does virtual machine (VM) and physical hosts management. The VM management includes VM creation, monitoring, and migration. If HC down, the services hosted by various hosts in DC can't be accessed outside the DC. Decentralized VM management avoids centralized failure by considering one of the hosts from DC as HC that helps in maintaining DC in running state. Each host in DC has many VM's with the threshold limit beyond which it can't provide service. To maintain threshold, the host's in DC does VM migration across various hosts. The data in migration is in the form of plaintext, the intruder can analyze packet movement and can control hosts traffic. The incorporation of security mechanism on hosts in DC helps protecting data in migration. This paper discusses an approach for dynamic HC selection, VM selection and secure VM migration over cloud environment.

• Annual Conference of KIPS
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• 2014.04a
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• pp.163-165
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• 2014

클라우드 컴퓨팅 기술의 발전 및 모바일 디바이스의 확산으로 데이터센터의 수요가 폭발적으로 증가하고 있고, 데이터 센터내 트래픽 또한 급증할 것으로 예측된다. 따라서 데이터센터 내에 서버용 확장 할 수 있고, 고장방지에 뛰어난 서버센트릭 네트워크 구조가 수많은 서버를 효율적으로 관리할 수 있는 대안으로 제시되었다. 본 논문에서는 서버센트릭 데이터센터에서 서버 배치를 통한 트래픽의 변화에 대해 분석하고 효율적으로 트래픽을 감소시키기 위한 휴리스틱(Heuristic) 접근방법을 제안한다.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.22 no.4
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• pp.205-212
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• 2010

In a typical data center, large numbers of IT sever racks are arranged multiple rows. IT environments, in which extensive electronic hardware is air-cooled, cooling system inefficiencies result when heated exhaust air from equipment prematurely mixes with chilled coolant air before it is used for cooling. Mixing of chilled air before its use with heated exhaust air results in significant cooling inefficiencies in many systems. Over temperatures may not only harm expensive electronic equipment but also interrupt critical and revenue generating services. Cool shield is a cost effective aisle partition system to contain the air in cold aisles and hot aisles of an IT server room. This paper focuses on the use of performance metrics for analyzing aisle partition system in data centers.

• Journal of Multimedia Information System
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• v.3 no.3
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• pp.63-68
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• 2016

Environmental downtime produces a significant cost to organizations and makes them unable to do business because what happens in the data center affects everyone. In addition, the amount of electrical energy consumed by data centers increases with the amount of computing power installed. Installation of physical Information Technology and facilities related to environmental concerns, such as monitoring temperature, humidity, power, flood, smoke, air flow, and room entry, is the most proactive way to reduce the unnecessary costs of expensive hardware replacement or unplanned downtime and decrease energy consumed by servers. In this paper, we present remote system for monitoring datacenter implementing using open-source hardware platforms; Arduino, Raspberry Pi, and the Gobetwino. The sensed data displayed through Arduino are transferred using Gobetwino to the nearest host server such as temperature, humidity and distance every time an object hitting another object or a person coming in entrance. The raspberry Pi records the sensed data at the remote location. The objective of collecting temperature and humidity data allows monitoring of the server's health and getting alerts if things start to go wrong. When the temperature hits $50^{\circ}C$, the supervisor at remote headquarters would get a SMS, and then they would take appropriate actions to reduce electrical costs and preserve functionality of servers in data centers.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.30 no.2
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• pp.83-91
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• 2018

A datacenter is a high energy consuming facility whose cooling energy consumption rate is 10~20 times larger than general office buildings. The higher the temperature of supply air from a CRAC (computer room air-conditioner) is supplied, the more energy efficient cooling is possible because of improving the COP of a chiller and advanced range of outdoor air temperature available for the economizer cycles. However, because the temperature of cold air flowing into server computers varies depending on air mixing configurations in a computer room, the proper supply air temperature must be considered based on the investigation of air mixing and heat dissipation. By these, this study aims to understand the effects of variation of the supply air temperature on the air flow distributions, temperature distributions and rack cooling efficiencies. Computational fluid dynamics (CFD) aided in conducting the investigation. As a result, the variation of the supply air temperature does not affect the air flow distributions. However, it mainly affects the temperature distribution. From the results of CFD simulations, Rack cooling indices (RCIHI and RCILO) were evaluated and showed the ideal state set at $19^{\circ}C$ of the supply air temperature.

• Journal of IKEEE
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• v.21 no.4
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• pp.353-357
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• 2017

In order to maintain numerous server systems used in enterprise and data center environments, the most important thing is to prevent the occurrence of UE (Uncorrectable Error) of each server system. With the recent development of cloud services, more memory modules are being used than ever before, while the operating frequency of server systems has increased and the process of developing memory has continued to shrink, making it more likely to fail. In these environments, there is a way to repair memory defects directly in the server system, but there is no currently available guideline to use it effectively. In this paper, we propose a method to effectively prevent memory failure in a server system based on the observation and analysis of memory failure phenomenon in existing system.

• International Journal of Internet, Broadcasting and Communication
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• v.7 no.1
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• pp.42-48
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• 2015

Generally, the current commercial cloud system is hosted by the centralization large datacenter. However, the other clouding forms existed and one of them is the P2P cloud. The P2P Cloud is a distributed systems, is freedom to join and leave and is possible to provide the IaaS. Commonly, P2P Cloud System is based on Pure-P2P System. Since a number of connection paths exist, it has a high reliability and easily scalability of the network. However, there are disadvantages of the slow rate of route because of looking up the all peers in order to search for the peer. In this paper, it proposes the P2P cloud system based on super-peer P2P. Super-peer P2P system has fast routing time, because of searching for cluster unit and it also can has high reliability and high scalability. We designs the super Peer cloud service and proposes the system model and Resource Allocation Algorithm for IaaS in Super peer P2P environment.

• Journal of the Microelectronics and Packaging Society
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• v.23 no.2
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• pp.37-42
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• 2016

While datacenter operation cost increases with electricity price rise, many researchers study low-power processor based supercomputers to reduce power consumption of datacenters. Reliability of low-power processors for supercomputers can be of concern since the reliability of many low-power processors are assessed based on mobile use conditions. This paper assessed the reliability of low-power processor packages based on supercomputer use conditions. Temperature cycling was determined as a critical failure cause of low-power processor packages through literature surveys and failure mode, effect and criticality analysis. The package temperature was measured at multiple processor load conditions to examine the relationship between processor load and package temperature. A physics-of-failure reliability model associated with temperature cycling predicted the expected lifetime of low-power processors to be less than 3 years. Recommendations to improve the lifetime of low-power processors were presented based on the experimental results.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.42 no.3
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• pp.612-622
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• 2017

Long-lived flowed termed as elephant flows in data center networks have a tendency to consume a lot of bandwidth, leaving delay-sensitive short-lived flows referred to as mice flows choked behind them. This results in non-trivial delays for mice flows, eventually degrading application performance running on the network. Therefore, a datacenter network should be able to classify, detect, and visualize elephant flows as well as provide QoS guarantees in real-time. In this paper we aim to focus on: 1) a proposed framework for real-time detection and visualization of elephant flows in SDN using sFlow. This allows to examine elephant flows traversing a switch by double-clicking the switch node in the topology visualization UI; 2) an approach to guarantee QoS that is defined and administered by a SDN controller and specifications offered by OpenFlow. In the scope of this paper, we will focus on the use of rate-limiting (traffic-shaping) classification technique within an SDN network.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.24 no.2
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• pp.411-429
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• 2014

As cloud computing has enabled, a variety of cloud services has come into wide use. Thus, cloud computing products can be easily identified in the IT market. Common Criteria is international standards for security evaluation performed of IT products. In addition, Consumers can be used as a objective guideline for the evaluation results. And, it is a provides for protection profile(security target of security products). For general, IT products are providing the protection profile. However, for cloud-related products of protection profile is not being provided. Thus, about cloud security products, there is no way for evaluation. Therefore, in this paper, we propose protection profile on cloud database management system for the secure cloud environment in common criteria.