• Korean Journal of Pharmacognosy
• /
• v.34 no.4 s.135
• /
• pp.324-326
• /
• 2003

The methanol (MeOH) extract and ist fractions of Taraxacum mongolicum (Compositae) were examined for their scavenging effects on 1,1-diphenyl-2- phenylhydrazyl (DPPH) and superoxide radicals, and hepatoprotective effects on tacrine-induced cytotoxicity in human hepatoma cell line, Hep G2 cells. Both methylene chloride $(CH_2Cl_2)$ and butanol (n-BuOH) soluble fractions of the MeOH extract showed the free radicals scavenging and hepatoprotective effects. From these results, it is suggested that hepatoprotective effect of these fractions partly relies on their free radical scavenging activity.

• Journal of the Korean Solar Energy Society
• /
• v.30 no.5
• /
• pp.77-84
• /
• 2010

This paper presents the continuous commissioning process, information on the case study facility, improved system operation, and building energy consumption measures before and after continuous commissioning implementation. Continuous commissioning is an ongoing process to resolve operating problems, improve comfort, optimize energy use and identify retrofits for existing commercial and institutional buildings and central plant facilities. Continuous commissioning process consists of two phases. The first phase is the project development phase and the second phase implements and verifies project performance. Results of a case study show that continuous commissioning implementation can reduce energy costs. The energy reports show the electricity savings of 22% and gas savings of 47% on an average.

• Journal of Korean Society of Industrial and Systems Engineering
• /
• v.27 no.2
• /
• pp.24-28
• /
• 2004

This paper considers a scheduling problem concerned with an assembly system where two components are first treated In their own parallel machines and then pulled to be assembled into a final product at a single assembly machine. The objective measure is the mean completion time of jobs(a finite number of products). Through characterizing solution properties, we obtain the worst case error bounds of an arbitrary permutation and a SPT based heuristic.

• Journal of Korean Society of Industrial and Systems Engineering
• /
• v.33 no.3
• /
• pp.154-161
• /
• 2010

This paper considers the simultaneously firing model for the artillery operations. The objective of this paper is to find the optimal fire sequence minimizing the final completion time of the firing missions of multiple artillery units for multiple targets. In the problem analysis, we derive several solution properties to reduce the solution space. Moreover, two lower bounds of objective are derived and tested along with the derived properties within a branch-and-bound scheme. Two efficient heuristic algorithms are also developed. The overall performances of the proposed branch-and-bound and heuristic algorithms are evaluated through various numerical experiments.

• Journal of Industrial Technology
• /
• v.26 no.A
• /
• pp.81-88
• /
• 2006

The Chun-cheon Citizen's Bell was cast in memory of hosting the 2010 world leasure conference and a striking ceremony was held at the city hall on December 31, 2005. In this study, vibration and sound of the bell are measured and the property of the magnificent sound of the bell is scientifically investigated. Frequency components making the sound are identified and how the frequency components decrease with time is observed using waterfall plot(3-dimensional frequency spectrum). Beat characteristics of the hum(1st frequency) and the fundamental(2nd frequency)are examined by experiment. Directivity of the sound radiation of the bell is examined by measuring the vibration and sound in several directions. Duration of the vibration and the sound is estimated using damping ratio.

• Proceedings of the KIEE Conference
• /
• 2015.07a
• /
• pp.278-279
• /
• 2015

한전 계통의 수도권 부하 밀집과 지중화 선로 증가로 인해 수도권 345kV 계통 과전압이 큰 문제가 되고 있다. 조상설비 투입 후에도 과전압이 문제가 되는 경우, 과전압 해소를 위한 다른 방안이 필요하다. 본 논문에서는 345kV 과전압 해소를 위한 345kV-154kV 변압기 탭조절 방안을 검토하였다. 효율적인 과전압 해소를 위해 탭 감도를 이용하여 탭 조절을 수행하였다. 또한 일반적인 경우 345kV-154kV 변압기의 2차측 전압을 올리면 1차측 전압이 떨어지지만 본 논문에서는 그렇지 않은 경우를 찾아내고 해당 원인을 분석하였다. 모의를 위한 데이터는 2014년 한전 과전압 모의 데이터를 사용하였다.

• Journal of applied mathematics & informatics
• /
• v.7 no.3
• /
• pp.739-763
• /
• 2000

We are concerned with mathematical analysis related to the bi-pointwise control for a mixed type of wave equation. In particular, we are interested in the systematic build-up of the bi-pointwise control actuators;one at the boundary and the other at the interior point simultaneously. The main purpose is to examine Hilbert Uniqueness Method for the setting of bi-pointwise control actuators and to establish relevant algorithm based on our analysis. After discussing the weak solution for the state equation, we investigate bi-pointwise control mechanism and relevant mathematical analysis based on HUM. We then proceed to set up an algorithm based on the conjugate gradient method to establish bi-pointwise control actuators to halt the system.

• Korean Management Science Review
• /
• v.25 no.3
• /
• pp.45-57
• /
• 2008

This paper considers a genetic algorithm for sequencing activities and allocating resources to reduce the over all completion time of workflow in the presence resource constraints. The algorithm provides an integrated solution for two sub-problems. The first is to decide the priority for the activities which require the same resource. The other problem is to select one among available resources for each activity by considering the incurred setup time and the performance factor of each resource. We evaluate the algorithm performance for three different kinds of workflows including parallel structures. Computational results show that the proposed algorithm is more effective than a previous work.

• Journal of Korean Neurosurgical Society
• /
• v.30 no.10
• /
• pp.1224-1228
• /
• 2001

Germinoma is a rare central nervous system neoplasm in children and young adults. It is well known that a malignant primary neoplasm can be cured by conventional radiation therapy alone or reduced-volume and field irradiation in combination with chemotherapy. The authors report a very rare case of a pineal germinoma, which was completely disappeared after repeated diagnostic brain computed tomography(CT) with review of pertinent literature. There has been neither tumor recurrence nor metastasis during follow-up period.

• Proceedings of the KIPE Conference
• /
• 2010.07a
• /
• pp.581-584
• /
• 2010

The background of this paper is the HVDC concept design of Jeju HVDC #2, which will be operated at 2011. The concept design is the first step of HVDC design procedures and the contents handled in this procedure are operation conditions, short circuit ratios(SCR) and interactions between AC network and HVDC. The operating conditions are based on the reliability of HVDC and AC network, SCR is related to HVDC stability and overvoltage and the interaction is between HVDC and other AC equipments, that are FACTS, generator and HVDC. The results of this paper are a keystone of HVDC #2 design.