• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.12
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• pp.8700-8706
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• 2015

The first driving device of the power bogies for the Korean high-speed railway vehicle consists of the traction motor (TM) and the motor reduction gears unit (MRU). Although TM and MRU are the mechanically integrated structures, their time between overhauls (TBO) have two separate intervals due to different technical requirements(i.e. TBO of MRU: $1.8{\times}10^6km$, TBO of TM: $2.5{\times}10^6km$). Therefore, to reduce the unnecessary number of preventive maintenances, it is important to evaluate the optimal TBO with a viewpoint of reliability-center maintenance towards cost-effective solution. In this study, derived from the field data in maintenance, fault tree analysis and failure rate of the subsystem considering criticality of the components are evaluated respectively. To minimize the conventional total maintenance cost, the same optimal TBO of the components is derived from genetic algorithm considering target reliability and improvement factor. In this algorithm, a chromosome which comprised of each individual is the minimum preventive maintenance interval. The fitness function of the individual in generation is acquired through the formulation using an inverse number of the total maintenance cost. Whereas the lowest common multiple method produces only a four percent reduction compared to what the existing method did, the optimal TBO of them using genetic algorithm is $2.25{\times}10^6$km, which is reduced to about 14% comparing the conventional method.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.16 no.7 s.98
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• pp.671-680
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• 2005

The CFL linearisation chip which is one of key devices in ultra-narrowband mobile radio transmitter using CQPSK digital modulation method is designed and implemented with $0.35{\mu}m$ CMOS technology. The reduced size and low cost of transmitter are available by the use of direct-conversion and CFL ASIC chip, which improve the power effi챠ency and linearity of transmitting path. In addition, low power operation is possible through CMOS technology The performance test results of transmitter show -25 dBc improvement of IMD level at the 3 kHz frequency offset and then satisfy FCC 47 CFR 90.210 E emission mask in the operation of CFL ASIC chip. At that time, the transmitting power is about PEP(Peak-to-Envelope Power) 5 W. The main parameters to improve the transmitting characteristic and to compensate the distortion in feed back loop such as DC-offset, loop gain and phase value are interfaced with notebook PC to be controlled with S/W.

• Journal of the Microelectronics and Packaging Society
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• v.15 no.3
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• pp.27-33
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• 2008

With increasing use of portable appliances such as PDA and cellular phone, changing environment of applications requires higher solder joint reliability. The ENIG (Electroless Nickel Immersion Gold) process has been widely used for fine pitch SMT (Surface Mount Technology) and BGA (Ball Grid Array) packaged devices due to its benefits including excellent solderability, high uniformity and substantial legibility throughout the packaging process. Its brittle fracture of solder, however, has received increasingly attentions. It was Down that fracture brittleness is mainly related with black pad resulting from galvanic nickel corrosion and P-enriched layer formation between the IMC (Intermetallic Compounds) and electroless nickel layer. Theoretically, smooth electroless Ni layer was blown to have a advantages in minimizing the black pad phenomenon by uniform solution exchange during immersion gold plating. Nevertheless, how to control the surface morphology of electroless Ni layer has been hardly blown. This study investigates an effect of surface morphology of Cu underlayer on surface morphology of electroless Ni layer. To obtain various kinds of surface morphology of Cu layer, two types of Cu etching chemical and a number of Cu etching treatment were applied.

• Journal of Chest Surgery
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• v.32 no.5
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• pp.456-460
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• 1999

Background: Thoracic sympathectomy for hyperhidrosis has been recognized as an effective treatment using thoracoscopic devices and operative techniques, but the satisfaction has decreased due to a compensatory hyperhidrosis. Therefore, the postoperative results and compensatory hyperhidrosis were analyzed. We also measured the temperature differences in the hand and foot during the preoperative and postoperative periods and measured the blood flow of upper and lower extremities. Material and Method: From December 1995 to July 1998, total of 47 patients with hyperhidrosis underwent sympathectomy via VATS at the Department of Thoracic and Cardiovascular Surgery, Kangnam St. Mary's Hospital. The patients were evaluated for preoperative and postoperative temperature changes on the finger and toe, and preoperative and postoperative blood flows were measured by the Doppler examination on the digital artery, radial artery and dorsalis pedis artery. Result: There were no operative deaths but some complications existed: 7 pneumothorax, 3 recurrence and 1 Honor syndrome. Ninety-five percent of the patients also had compensatory sweating especially in the trunk. There were 5 patients who regretted recurring the operation because of the compensatory sweating. Sweating decreased in 46% of the sole hyperhidrosis patients. The temperature difference between preoperation and postoperation was 1$^{\circ}C$ on the right hand side and 1.9$^{\circ}C$ on the left hand side(P<0.05). There was no significant temperature difference on the sole. Blood flow increased significantly in the palm, but no difference in the sole. Conclusion: In conclusion, thoracic sympathectomy for hyperhidrosis is a safe and effective treatment but satisfaction has been decreased by the compensatory sweating; therefore, it is important to thoroughly explain the compensatory sweating prior to surgery. Improvement of the plantar hyperhidrosis is not due to a physiological change, but to a psychological stability.

• Management & Information Systems Review
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• v.28 no.4
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• pp.253-291
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• 2009

Expo, as one of the types of convention, is defined as the exhibition of which primary object is the public enlightenment. It displays lots of exhibits from countries around the world created or produced by advanced technologies, but its priority is actually on suggesting value of product, usability and creativity, not on seeking for purchasers of those products. Thus, the world's event Expo can be deemed as the place for educating visitors with various features in both current and future generation in terms of "experience". This study intends to grasp the attributes and elements of the host cities and to look into the formation of city image after being a spectator and the relation for suggesting systematic and rational measures on planning and promoting the Expo. For the foregoing measures, this study suggests effective management measures for Expo spectators by disclosing attributes of host cities, relationship with the formation of city images, and satisfactory relationship among Expo spectators. For achieving the purpose of this study, the relationship between spectators who visited the 'Cheonan 2009 Wellbeing Food Expo' and each element on the basis of the measuring devices deducted through a preparatory research. Based on the results deducted through positive analysis, it intends to expect qualitative improvement of 'Cheonan 2009 Wellbeing Food Expo' and to suggest measures for elevating satisfaction level of Expo spectators by displaying alternative elements for spectators' choice at the Expo and gives continuous suggestion on managing spectators.

• The Korean Journal of Pain
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• v.4 no.2
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• pp.127-132
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• 1991

Recently a non-electronic, disposable and portable infusor(Baxter infusor with patient control module, Baxter health care Co., Deerfield IL 60015 USA: BI $\bar{c}$ PCM) has been developed that will deliver both a continuous drug infusion as well as allow the patient to deliver extra doses of medication on a demand basis under predetermined limitation of analgesics. Patients may also not require as high analgesic dose rate to control pain when the acceptable and tolerable level of pain relief can be maintained by this device. From April l99l, we have used a total l93 units of BI $\bar{c}$ PCM. These units consisting of two components which one made by a balloon reservoir(capacity 65 ml, flow rate 0.5 ml/hr) to store medication and to regulate the pump power(490 torr), and another two PCMs to regulate additional analgesic administration by patients demand at intervals of 1S minutes and 60 minutes. The dose administered to the patient can be varied by changing the concentration of the infusate within the balloon reservoir. These devices were utilized for the pain control of 44 patients. These patients were divided into two groups. Twenty seven cases had cancer pain and 17 cases had non-cancer pain. The Touhy needle(No. l8 G.) tip was inserted into the epidural space and was used to guide the catheter to the spinal nerve level corresponding to the most painful area. The device was connected to the opposite site of the catheter tip and was filled with 60 ml of mixture solution such as 0.5% bupivacaine 15 ml, morphine HCl 10 mg, trazodone 10 ml, Tridol 3 ml and normal saline 31 ml were administed as the initial dose. When the initial dose was less effective, the next dose could be varied by increasing the concentration of bupivacaine, by adding more morphine (5~10 mg), and by reducing the volume of normal saline. Using these modules of drug self administration, we experienced the following: 1) Improvement of patient's self titration of analgesic requirement was provided. 2) The patients anxiety with pain recurrence resulting from delays in administering pain control medication was decreased significantly. 3) The working load accompanying with the single bolus injection as the usual method was reduced remarkably. 4) There was urinary retention in 5 cases and pruritus in 4 eases which developed as side effects but respiratory depression and vomiting was not encountered in a single case.

• Journal of Korean society of Dental Hygiene
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• v.12 no.6
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• pp.1119-1127
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• 2012

Objectives : The aim of this study was to examine the level of oral health knowledge, oral health importance, oral health status and oral health interest of the social workers engaged in child care facilities to analyze the influential factors on oral health promotion activities and provide the basic data for oral health promotion activities. Methods : The subjects in this study were those social workers engaged in child care facilities from May 15th to May 25th in 2011. The self-report questionnaires were distributed and withdrawn and then a total of 205 papers from the subjects that participated in this study were analyzed for the final analysis. Results : 1. Oral health knowledge had $12.16{\pm}1.66$ in a full score of 15 and oral health importance, oral health status and oral health interest were $1.12{\pm}0.36$, $2.80{\pm}0.50$ and $2.14{\pm}0.8$ respectively in a full score of 5. 2. According to the general characteristics, the difference analysis of cognition-recognition factors showed that singles had significantly higher oral health knowledge married couples (p<0.05) and the social workers unusing auxiliary oral hygiene devices had significantly higher oral health interest than those using them(p<0.01). 3. The mean of oral health promotion was $3.28{\pm}0.51$, characteristics of detailed specific-area were as follows ; the toothbrushing was $3.77{\pm}0.57$, the use of fluoride was $2.67{\pm}0.98$, periodic dental screening and treatment were $2.98{\pm}1.09$ and eating habits was $4.14{\pm}0.57$. These results generally showed tooth-brushing and eating habits show a little higher figures. 4. Considering the factors oral health promotion behaviors of social workers engaged in child care facilities, the higher oral health interest was, the higher oral health promotion behavior was. Conclusions : It seems that social workers engaged in child care facilities are required to pay attention to the importance of oral health and learn oral health knowledge, which will lead to much better improvement of oral health for children brought up by them.

• Journal of the Korean Society for information Management
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• v.34 no.3
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• pp.89-107
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• 2017

This study aims to compare information seeking behavior of 1300K users on PC and mobile phone. Transaction logs of 1300K, a major Korean shopping search engine, were analyzed. These transaction logs were collected over 1 month period, from April 1 to April 31, 2016. The results of this study show that there are a little more mobile sessions than PC sessions. Users conducted slightly more browsing on PCs than mobile phones, whereas users submitted queries more than two times on mobile phones than on PCs. Users clicked more search results on PCs than mobile phones, whereas users made important decision makings such as product purchases more on mobile phones than PCs. Top queries and categories were similar between PCs and mobile phones. Queries and categories on mobile phones were more focused than queries on PCs. Overall, mobile search behavior is more simple, passive, and focused than PC search behavior. The results of this study can be implemented to the effective improvement and development of search services for different devices.

• Journal of the Korean Society of Marine Environment & Safety
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• v.13 no.4
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• pp.55-63
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• 2007

The Group Digital Surveillance System for Fishery Safety and Security (GDSS-F2S) is to provide the target tracking information and the target identification information in order to secure an huge aquaculture farm-field from a thief. The two information, however, is not enough to indict the thief due to the lack of lawful evidences for the crime actions. To overcome this problem, we consider the target image information as one of solutions after discussion with the effective countermeasure tools for the crime actions with scenario-based analysis according to the geological feature of aquaculture farm-field. To capture the real-time image for the trespassing targets in the aquaculture farm-field area, we developed the image capture system which is consists of ultra sensitive CCD(Charge-Coupled Device) camera with 0.0001 Lux and supplementary devices. As results from the field tests for GDSS-F2S with image capture system, the high definite images of the vehicle number plate and shape, person's actions and features are obtainable not only day time but also very dark night without moon light. Thus it is cleary known that the improved GDSS-F2S with image capture system can provide much enough lawful evidences for the crime actions of targets.

• Journal of KIISE:Computer Systems and Theory
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• v.36 no.4
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• pp.274-282
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• 2009

Various location tracking sensors; such as GPS, INS, radar, and optical equipment; are used for tracking moving targets. In order to effectively track moving targets, it is necessary to develop an effective fusion method for these heterogeneous devices. There have been studies in which the estimated values of each sensors were regarded as different models and fused together, considering the different error characteristics of the sensors for the improvement of tracking performance using heterogeneous multi-sensor. However, the rate of errors for the estimated values of other sensors has increased, in that there has been a sharp increase in sensor errors and the attempts to change the estimated sensor values for the Sensor Probability could not be applied in real time. In this study, the Sensor Probability is obtained by comparing the RMSE (Root Mean Square Error) for the difference between the updated and measured values of the Kalman filter for each sensor. The process of substituting the new combined values for the Kalman filter input values for each sensor is excluded. There are improvements in both the real-time application of estimated sensor values, and the tracking performance for the areas in which the sensor performance has rapidly decreased. The proposed algorithm adds the error characteristic of each sensor as a conditional probability value, and ensures greater accuracy by performing the track fusion with the sensors with the most reliable performance. The trajectory of a UAV is generated in an experiment and a performance analysis is conducted with other fusion algorithms.