• Journal of Information Technology Applications and Management
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• v.26 no.5
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• pp.41-56
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• 2019

Recently great loss of life and property is occurring because of fire, natural disaster, earth quake, tsunami and so on. People spend 80~90% of their time indoor environment like office, supermarket, campus. Therefore Indoor navigation and guidelines system became so essential for most of all. Incase of emergency we must be careful earlier, in such a cases 5G kind of new technology may also cannot work. So immediate action and quick routing notification for guidelines and protection is the most. Considering this issue We proposed indoor evacuating guidance system based on microcontroller Wi-Fi board for Indoor APP using mobile. Focusing various kind of technology like, ok google, voice search APP we purposed node architecture based system. When we listen fire alarm while living inside the room. Then to be safe we connect with server and start Arduino UNO+IoT ESP8266 Wi-Fi shield version1-IoT module to store data in MySQL DB server. We make application to escape out from the building up-to the three exits giving information from source point to destination. Our program can send information to the users emergency location and situations. For this when the user get sound or vibration in their mobile device it indicate fire out near by. At that time we update message from Arduino to DB server for the fixed current position inside the building which give routing signal for that fire out location by changing values from 0 to 1. We have user in point 10 where user is near by. Later we detect Wi-Fi signal form Nodemcu as room of each floor and try to connect with user. Main purpose of this paper is to save life of people in short time and find out the shortest path up to nearest exits in the time of emergencies and rescue them.

• Proceedings of the SAREK Conference
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• 2006.06a
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• pp.938-943
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• 2006

The primary purpose of a computer room of data center and associated infrastructure is to support the operation of critical IT equipment. Traditionally, most owners of large critical data centers have been more than willing to accept a reasonable amount of computer room worker discomfort if necessary to support critical IT systems. All electrical equipment produces heat, which must be removed to prevent the equipment temperature from rising to an unacceptable level. Most information technology equipment and other equipment found in a data center or network room is air-cooled. Sizing a cooling system requires an understanding of the amount of heat produced by the equipment contained in the enclosed space, along with the heat produced by the other heat sources typically encountered.

• Proceedings of the Korea Contents Association Conference
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• 2007.11a
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• pp.234-237
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• 2007

We report on our experience on utilization of collaborative tools for KISTI high energy physics group. Our main subject will be the new EVO (Enabling Virtual Organization) server that we hosted recently at KISTI. The EVO is a next generation collaborative tool from CalTech high energy physics group with several improvements from its predecessor VRVS (Virtual Room Videoconferencing System). EVO has the same baseline structure as in VRVS. The network of servers lies at the heart of EVO structure and one server called Panda communicates with local clients called Koala.

• 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.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.25 no.7
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• pp.371-376
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• 2013

Recently, many studies related to reducing the energy consumption in data centers have been conducted. These studies have mainly focused on the air intake and exhaust system of a computer room air handling unit (CRAH) in the server room, diffuser type, suppression and discharge of the heat generated from the server, and the air-side economizer system. In this study, the energy consumption of the conventional central chilled water cooling system is compared with the energy consumption of the air-side economizer system. We also examined how changes of differential pressure by each filter have influenced energy consumption, using the power usage effectiveness (PUE). Results show that the PUE was improved, and energy consumption decreased, by applying the air-side economizer system.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.449-452
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• 2005

For home networking system with a function of air quality monitoring, a wireless sensor module with several air quality monitoring sensors was developed for indoor environment monitoring system in home networking. The module has various enlargements for various kinds of sensors such as humidity sensor, temperature sensor, CO2 sensor, flying dust sensor, and etc. The developed wireless module is very convenient to be installed on the wall of a room or office, and the sensors in the module can be easily replaced due to well designed module structure and RF connection method. To reduce the system cost, only one RF transmission block was used for sensors' signal transmission to 8051 microcontroller board in time sharing method. In this home networking system, various indoor environmental parameters could be monitored in real time from RF wireless sensor module. Indoor vision was transferred to client PC or PDA from surveillance camera installed indoor or desired site. Web server using Oracle DB was used for saving the visions by web-camera and various data from wireless sensor module.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.7
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• pp.726-733
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• 2016

In this study, a computer simulation of the three types of air distribution systems, open type system, aisle partition system and aisle containment system, to evaluate the applicability of the aisle partition system on a data center server room. The variables of the simulation were the height and location of the partition fixed on the top server rack. The energy efficiency of the air distribution systems were confirmed to be excellent in the order of the aisle containment system, aisle partition system, and open type system. In the cold aisle partition system, the height of the partition that can be effective in saving cooling energy by obstructing sufficient air recirculation was found to be more than 0.9m. In the hot aisle partition system, the height of the partition was found to be more than 0.8m.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.9 no.1
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• pp.61-66
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• 2009

In this paper, an example of implementation of a embedded system technology for web based monitoring and control system is presented. For it interfaces with target board as an embedded system was developed, which was applied to specific green room model and verified of its usefulness. We implemented client/server socket programs using Java classes, and web based green room monitoring and control system as an user interface using JavaApplet. The implemented system did send information of green room model to client programs well on TCP/IP and control signals from client to green room model well too.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.330.1-330.1
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• 2014

개인용 노트북, 태블릿 PC, 핸드폰 기술 발전에 의해 언제 어디서나 데이터를 작성하고 기록하는 일들이 가능해졌다. 특히 cloud 시스템을 이용하여 데이터를 휴대기기에 직접 저장하지 않고 server에 기록하는 일들이 가능해짐에 따라 server 기기의 성능, server-room power 및 space 에 대한 관심이 증가하였다. Storage class memory (SCM) 이란 memory device와 storage device의 장점을 결합한 memory를 일컫는 기술로 현재 소형 디바이스 부분부터 점차 그 영역을 넓히고 있다. 그중 phase change material을 이용한 phase change memory (PCM) 기술이 가장 각광받고 있다. PCM의 경우 scaling됨에 의해 cell간의 열 간섭으로 인한 data 손실의 우려가 있어 cell의 면적을 최소화 하여 소자를 제작하여야 한다. 기존의 sputtering등의 PVD 방법으로는 한계가 있어 ALD 공정을 이용한 PCM에 대한 연구가 활발히 진행중이다. 특히 tellurium 원료기체로 silyl 화합물 [1]을 사용하여 주로 $Ge_2Sb_2Te_5$의 조성에 초점을 맞춰 진행되고 있으나, 세부 공정에 대한 기본적인 연구는 미비하다. 본 연구에서는 Ge-Sb-Te 3원계 박막을 형성하기 위한 Sb-Te 화합물의 증착 공정에 대한 연구를 수행하였다. 특히 원료기체로 Si이 없는 새로운 Te 원료기체를 이용하여 조성 조절을 하였고, 박막의 물성을 분석하였다. 또한 공정온도에 따른 박막의 물성 변화를 분석하였다.

• Proceedings of the Korean Statistical Society Conference
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• 2000.11a
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• pp.105-108
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• 2000

We consider a Markovian retrial queue with waiting space in which the service rates and retrial rates depend on the number of customers in the service facility and in the orbit, respectively. Each arriving customer from outside or orbit decide either to enter the facility or to join the orbit in Bernoulli manner whose entering probability depend on the number of customers in the service facility. In this paper, a stochastic order relation between two bivariate processes (C(t), N(t)) representing the number of customers C(t) in the service facility and N(t) one in the orbit is deduced in terms of corresponding parameters by constructing the equivalent processes on a common probability space. Some applications of the results to the stochastic bounds of the multi-server retrial model are presented.