• Journal of Aerospace System Engineering
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• v.8 no.2
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• pp.49-54
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• 2014

The main purpose of Korea Space Launch Vehicle II(KSLV-II) Program is to develop a domestic launch vehicle that can deliver a 1.5ton class application satellite into a Low Earth Orbit(600~800km). The data management is an essential factor in systems engineering for success of large-scale complex systems development, and it systematically manages the information and technical data for the total life-cycle of a system. In this paper, data management policies and processes on KSLV-II program are presented, and product life-cycle management system for KSLV-II program is also presented.

• Proceedings of the Korean Society for Bioinformatics Conference
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• 2000.11a
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• pp.41-44
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• 2000

With the advent of DNA microarray and "chip" technologies, gene expression in an organism can be monitored on a genomic scale, allowing the transcription levels of many genes to be measured simultaneously. Functional interpretation of massive expression data and linking such data to DNA sequences have become the new challenges to bioinformatics. I will us yeast cell cycle expression data analysis as an example to demonstrate how special database and computational methods may be used for extracting functional information, I will also briefly describe a novel clustering algorithm which has been applied to the cell cycle data.

• Transactions of the Korean Society of Automotive Engineers
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• v.9 no.6
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• pp.94-102
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• 2001

The thermodynamic second law analysis, which means available energy or exergy analysis, for the indicated performance of Otto cycle engine has been carried out. Each operating process of the engine is simplified and modeled into the thermodynamic cycle. The calculation of the lost work and exergy through each process has been done with the thermodynamic relations and experimental data. The experimental data were measured from the test of single cylinder Otto cycle engine which operated at 2500 rpm, WOT(Wide Open Throttle) and MBT(Minimum advanced spark timing for Best Torque) condition with different fuels: gasoline, methanol and mixture of butane-methanol called M90. Experimental data such as cylinder pressure, air and fuel flow rate, exhaust gas temperature, inlet gas temperature and etc. were used for the analysis. The proposed model and procedure of the analysis are verified through the comparison of the work done in the study with experimental results. The calculated results show that the greatest lost work is generated during combustion process. And the lost work during expansion, exhaust, compression and induction process follows in order.

• Journal of Korean Academy of Nursing
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• v.50 no.1
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• pp.147-157
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• 2020

Purpose: This descriptive study aimed to identify the menstrual cycle characteristics and premenstrual syndrome (PMS) prevalence in Korean young adult women using the retrospective and prospective Daily Record of Severity of Problems (DRSP). Methods: In the first stage, participants included 151 nursing students studying in a university located in Seoul. Data were collected from April 20 to June 2, 2017, using the questionnaire on menstrual characteristics, pictorial blood assessment chart, and retrospective DRSP. In the second stage, participants included 17 students with PMS, based on the screening conducted in the first stage. Data were collected using the prospective DRSP from May 29 to 2 September 2, 2017. Results: Of the study sample, 104 participants (68.9%) had regular periods. Those with regular periods had 11.97 periods annually with a menstrual cycle of 29.38 days and a period duration of 5.72 days. Fifty-five participants (37.4%) showed menorrhagia. Sixty-four participants (42.4%) were found to have PMS based on their retrospective DRSP. When the ratio of women (52.9%) with PMS shown in the prospective DRSP was used as a positive predictive value, the estimated PMS prevalence was 22.4%. Conclusion: This study provides clinically significant PMS prevalence among Korean young adult women, positive predictive value of the retrospective DRSP, and valid data to basically understand the menstrual cycle characteristics experienced by these women.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.16 no.6
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• pp.1849-1876
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• 2022

Wireless Sensor Network (WSN) is considered as an integral part of the Internet of Things (IoT) for collecting real-time data from the site having many applications in industry 4.0 and smart cities. The task of nodes is to sense the environment and send the relevant information over the internet. Though this task seems very straightforward but it is vulnerable to certain issues like energy consumption, delay, throughput, etc. To efficiently address these issues, this work develops a cross-layer model for the optimization between MAC and the Network layer of the OSI model for WSN. A high value of duty cycle for nodes is selected to control the delay and further enhances data transmission reliability. A node measurement prediction system based on the Kalman filter has been introduced, which uses the constraint based on covariance value to decide the scheduling scheme of the nodes. The concept of duty cycle for node scheduling is employed with a greedy data forwarding scheme. The proposed Duty Cycle-based Greedy Routing (DCGR) scheme aims to minimize the hop count, thereby mitigating the energy consumption rate. The proposed algorithm is tested using a real-world wastewater treatment dataset. The proposed method marks an 87.5% increase in the energy efficiency and reduction in the network latency by 61% when validated with other similar pre-existing schemes.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.23 no.7
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• pp.513-519
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• 2011

The object of this study is to investigate the performance characteristics of refrigerators using a single-circuit multi cycle and a bypass two-circuit multi cycle. Each refrigeration cycle was tested by varying secondary fluid mass flow rate and temperature. Based on the experimental data, the optimum refrigerant charge was 48 g and the COP at the optimum secondary fluid mass flow rate was 1.53 for the single-circuit multi cycle. For freezer(F)-only mode, both the single-circuit multi cycle and the bypass two-circuit multi cycle were operated at overcharge conditions, resulting in an increase of the secondary fluid mass flow rate. The maximum COPs of the single-circuit multi cycle and the bypass two-circuit multi cycle were 1.22 and 1.35, respectively. The COP increased by 10.7% with the application of the bypass two-circuit multi cycle.

• Transactions of the Korean Society of Automotive Engineers
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• v.22 no.7
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• pp.117-126
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• 2014

Recently, due to various environmental problems such as global warming, increasing of international oil prices and exhaustion of resource, a paradigm of world automobile market is rapidly changing from vehicles using internal combustion engine to eco-friendly vehicles using electric power such as EV (Electric Vehicle), HEV (Hybrid Electric Vehicle), PHEV (Plug-in Hybrid electric Vehicle) and FCEV (Fuel Cell Electric Vehicle). There are many driving cycles for performance evaluation of conventional vehicles. However there is a lack of researches on driving cycle for EV. This study is composed of part 1 and part 2. In this paper part 1, in order to develop urban driving cycle for performance evaluation of electric vehicles, Gwacheon-city patrol route of police patrol car was selected. Actual driving test was performed using EV. The driving data such as velocity, time, GPS information etc. were recorded. GUDC-EV (Gwacheon-city Urban Driving Cycle for Electric Vehicles) including road gradient was developed through the results of analyzing recorded data. Reliability of the driving cycle development method was substantiated through comparison of electricity performance. In the second part of this study, the developed driving cycle was compared to simulation result of the existing urban driving cycle. Verification of the developed driving cycle for EV performance evaluation was described.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.22 no.6
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• pp.91-97
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• 2022

There is hare and tortoise racing algorithm(HTA) for single-source(SS) singly linked list(SLL) with O(n) time complexity. But the fast method is unknown for general graph with multi-source, multi-destination, and multi-branch(MSMDMB). This paper suggests linear time cycle detection algorithm for given undirected and digraph with MSMDMB. The proposed method reduced the given graph G contained with unnecessary vertices(or nodes) to cycle into reduced graph G' with only necessary vertices(or nodes) to cycle based on the condition of cycle formation. For the reduced graph G', we can be find the cycle set C and cycle length λ using linear search within linear time. As a result of experiment data, the proposed algorithm can be obtained the cycle for whole data.

• Proceedings of the Safety Management and Science Conference
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• 2007.04a
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• pp.309-322
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• 2007

This paper shows application guide of dependability data from the field, life cycle costing, and maintainability. Moreover, this study introduces mathematical expressions and predictions for reliability, availability and maintainability. This paper also shows compliance test procedures for steady-state availability, and application of Markov techniques.

• Proceedings of the Korea Database Society Conference
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• 1999.06a
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• pp.75-84
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• 1999

본 논문에서는 지식에 대한 개념을 정의하기 보다 지식의 life-cycle을 통한 지식의 생성과 소멸을 모델화함으로 지식을 설명하려 한다. 본 논문은 노나카의 지식 창조 모델을 기반으로 하고 기존의 KMS들을 분석하여 일반적인 지식 life-cycle 모델을 도출하였으며, 기존 모델의 문제점을 보완하여 새로운 지식 life-cycle 모델을 만들었다. 이 모델과 앞으로의 지식관리 시스템 발전 방향을 고려하여 지식 관리 시스템 아키텍쳐를 제시하였다. 본 논문에서는 이 아키텍쳐를 근거로 지식 관리 시스템을 구현하기 위한 6개의 컴포넌트를 도출하였다 6개의 컴포넌트는 지식 생성, 지식 분배, 지식 측정, 지식연결, 지식 검색, 지식 저장이다. 이 컴포넌트들로 지식 관리 시스템의 prototype을 구현해 본 결과 지식life-cycle을 단계적, 부분적으로 지원하지만 부족한 부분이 있는 것을 발견하였다. 향후에는 지식 생성과 지식 연결 컴포넌트를 강화하여 전체적인 지식 life-cycle을 지원할 예정이다.