• The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.8 no.1
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• pp.37-45
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• 1994

A method of optimal active and reactive power control for economic operation in electrical power system is presented in this paper. The major features and techniques of this paper are as follows: 1) The method presented for obtaining the equivalent active power balance equation applying the sparse Jacobian matrix of power flow equation instead of using B constant as active power Balance equation considering transmission loss, and for determining directly optimal active power allocation without repeating calculations. 2) More reasonable and economic profit by minimizing total fuel cost of thermal power plants instead of using transmission loss as objective function of reactive Power control can be achieved. 3) Particularly in reactive power control, computing time can be considerably reduced by using Fuzzy Linear Programming instead of using conventional Linear Programming.

• Korean Journal of Construction Engineering and Management
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• v.6 no.4 s.26
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• pp.80-90
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• 2005

Activity durations retain probabilistic and stochastic natures due to diverse factors causing the delay or acceleration of activity completion. These natures make the final project duration to be a random variable. These factors are the major source of financial risk. Extending the Stochastic Project Scheduling Simulation system (SPSS) developed in previous research; this research presents a method to estimate how the final project duration behaves when activity durations change randomly. The final project cost is estimated by considering the fluctuation of indirect cost, which occurs due to the delay or acceleration of activity completion, along with direct cost assigned to an activity. The final project cost is estimated by considering how indirect cost behaves when activity duration change. The method quantifies the amount of contingency to cover the expected delay of project delivery. It is based on the quantitative analysis to obtain the descriptive statistics from the simulation outputs (final project durations). Existing deterministic scheduling method apply an arbitrary figures to the amount of delay contingency with uncertainty. However, the stochastic method developed in this research allows computing the amount of delay contingency with certainty and certain degree of confidence. An example project is used to illustrate the quantitative analysis method using simulation. When the statistical location and shape of probability distribution functions defining activity durations change, how the final project duration and cost behave are ascertained using automated sensitivity analysis method

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.47 no.1
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• pp.91-96
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• 2010

In this paper, a deformation measurement technology of the nuclear fuel rod is proposed. The deformation measurement system include high definition CCD or CMOS image sensor, lens, semiconductor laser line beam marker, and optical & mechanical accessories. The basic idea of the deformation measurement is to illuminate the outer surface of the fuel rod with collimated laser line beam at an angle of 45 degrees or higher. The relative motion of the fuel rod in the horizontal direction causes the illuminated laser line beam to move vertically along the surface of the fuel rod. The resulting change of laser line beam position in the surface of the fuel rod is imaged as the parabolic beam in the high definition CCD or CMOS image sensor. From the parabolic beam pattern, the ellipse model is extracted. And the slope of the long and the short axis of the ellipse model is found. The crossing point between the saddle point of the parabolic beam and the long & short axis of the ellipse model is taken as the feature of the deformed fuel rod. The vertical offset between feature points before and after fuel rod deformation is calculated. From the experimental results, $50\;{\mu}m$ inspection resolution is acquired using the proposed method, which is three times enhanced than the conventional criterion ($150\;{\mu}m$) of the guide for the inspection of the nuclear fuel rod.

• 한국생물공학회:학술대회논문집
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• 2000.04a
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• pp.512-515
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• 2000

In this study, ${\delta}-aminolevulinic$ acid, porphobilinogen, glycine and levulinic acid were succesfully separated by capillary electrophoresis(CE). We established the separative conditions of the mixture containing four components by CE. The borate buffered solution was used for CE electrolyte, and its pH was adjusted to $9.25{\sim}9.42$. Under constant current or constant voltage, higher concentraion of borate produced better resolution of four components, but adversely affected migration rates , resulting in longer analysis time. While migration time was faster with increase in applied voltage, but adversely affected resolution. Each component was separated well in borate buffer of 30mM at the applied voltage of 20kV.

• The Transactions of the Korean Institute of Power Electronics
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• v.3 no.2
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• pp.85-91
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• 1998

This paper describes an study electric injection system for diesel engines. It is needed effective fuel injection which controls the solenoid valve of fuel pump. To solve this, this paper proposes DCC-PWM method which can realize fast reply and low holding current for solenoid valve on/off. For the proposed design method, simulation tools of ACSL are used to analyze the system. And the single-chip microcomputer is used to reduce the size of controller and to improve flexibility. And the systems validity can be verified through the experimental results.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.12 no.6
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• pp.155-164
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• 2012

The compression of software development schedule has a limit without regarding to a development manpower. However, the actually developed softwares includes the impossible short time or unreal long time date. Previously suggested models are driving the development schedule from all of the actually developed software without considering these constraints. This paper recommends a standard of minimum and the most suitable development time period. This paper has chosen a criterion that shows the best development schedule among 5 criteria based on the actually performed projects. Moreover, this paper suggests a model that estimates the development schedule based on the best criterion.

• Journal of KIISE:Information Networking
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• v.37 no.6
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• pp.444-452
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• 2010

To avoid a channel zapping delay, the device needs to predict a next channel and must download it. Previous researches suggest algorithms based on assumption by utilizing many data. How to select and download future channels is a main issue in IPTV system. Most proposal based on assumption do not guarantees complete performance of channel zapping. In this paper, we suggest an effective method to avoid a channel zapping time with a constant performance by using a number remote controller key information.

• Quality Improvement in Health Care
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• v.15 no.1
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• pp.89-100
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• 2009

문제: 소화기병검사실에서 대장내시경 검사의 부도건수가 최근 월 200명 정도로 예약인원의 16%에 달한다. 이는 본원 외래진료 부도율이 평균 10%인 것과 비교할 때 상당히 높은 결과이므로 대장내시경 예약환자를 대상으로 부도율 관리를 위한 활동이 필요하였다. 목적: 외래 및 입원환자의 부도건수 및 부도환자의 특성을 분석하고, 개선활동을 통하여 대장내시경 검사의 부도율을 줄인다. 의료기관: 서울 아산병원. 질 향상 활동: 부도관리를 위한 개선활동으로 SMS 횟수를 2주전, 4일전, 1일전 3회로 변경하고, 내용도 각 시기마다 차별화하였다. 대장내시경 검사 예약을 하고 기다리는 환자를 대상으로 처방일 순, 예약 날짜순서 등 필요한 항목 순으로 볼 수 있는 리스트가 필요하여 예약대기 프로그램을 개발하였고, 처방일로부터 2주 이내 자동예약을 금지하였다.(7월 10일부터 시작) 예약대기명단에 있는 환자를 대상으로 전화로 예약 변경을 하여 2주 이내에는 예약의 빈자리가 없도록 하였다. 미리 부도를 예측하여 추가로 예약하던 방법에서 정원조정을 하여 정원 외 추가 예약을 하지 않았다. 입원환자 일정관리를 위하여 일정관리 프로그램을 개발하여 타과의뢰 회신을 하는 전임의가 직접 날짜를 전산에 입력하여 회신과 동시에 검사실, 담당주치의, 담당 간호사가 모두 일정을 확인할 수 있도록 하였으나 프로그램이 늦어져 9월 12일부터 시행하였다. 개선효과: 부도건수가 개선 전 8주 동안 385건(예약인원 대비 16%) 에서 개선 후 6주의 평가기간 동안 256건(예약인원대비 14.1%)으로 129건이 감소하였으며, 검사 1-2일전 일정 변경 연락 환자 감소 및 검사 비용 수납 환자의 부도건수가 감소하였다. 대장내시경 검사 예약대기 프로그램 운영 및 예약 변경 전화 활동으로 2달씩 기다리던 환자의 예약일을 약 한 달 정도 단축하여 줄 수 있었다. 검사 정원 관리의 결과로 검사 예약 시 예약기준이 명확해지고, 부적절한 예약으로 인한 검사지연 등이 확실히 줄었다. 또한 입원환자 일정관리 프로그램 적용으로 입원환자의 검사일정과 관련된 전화업무는 확실히 줄어들 것으로 예상된다.

• Transactions of the KSME C: Technology and Education
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• v.1 no.1
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• pp.129-138
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• 2013

Constant airflow should be kept in order to operate a constant-fired boiler of thermal power plants. Main Bearing Assembly Unit which rotates the ventilation fan does very important role to maintain constant airflow. However, the demand to the output of power is getting increased while the quality level of coal is getting worse than the initial level of design criteria. Especially cost wise operation considering increasing output and the difficulty to supply good quality coal drive increasing supply of low quality coal. As a result, the service life of Main Bearing Assembly is getting shorter till 2~3 years which is just a half of the life of original design. In this study, what causes to shorten the service life of Main Bearing Assembly Unit is analyzed through the reverse engineering and analysis and how to improve the service life more than two times to current situation is explained.

• Journal of the Korea Society of Computer and Information
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• v.20 no.4
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• pp.111-117
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• 2015

The exam scheduling problem has been classified as nondeterministic polynomial time-complete (NP-complete) problem because of the polynomial time algorithm to obtain the exact solution has been unknown yet. Gu${\acute{e}}$ret et al. tries to obtain the solution using linear programming with $O(m^4)$ time complexity for this problem. On the other hand, this paper suggests chromatic number algorithm with O(m) time complexity. The proposed algorithm converts the original data to incompatibility matrix for modules and graph firstly. Then, this algorithm packs the minimum degree vertex (module) and not adjacent vertex to this vertex into the bin $B_i$ with color $C_i$ in order to exam within minimum time period and meet the incompatibility constraints. As a result of experiments, this algorithm reduces the $O(m^4)$ of linear programming to O(m) time complexity for exam scheduling problem, and gets the same solution with linear programming.