• Proceedings of the Korean Institute Of Construction Engineering and Management
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• 2004.11a
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• pp.261-264
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• 2004

The study, by reviewing and analysing the system of occupational education and training, aims to provide some substantial informations for the activation of occupational education and training in the construction sector. The result shows that the current system doesn't substantially reflect the realities of employment structure in the sector, and thus, fails to respond to skilled-worker development. It is also observed that most of the occupational education and training institutions have difficulties in recruiting trainees due to daily construction workers' negative attitudes toward the current system. Therefore, it is necessary i) to improve occupational education and training system, ii) to tackle in-depth analysis of daily construction workers' reasons for the negative perceptions, and iii) to develop the responding alternatives.

• Journal of the Korean Ceramic Society
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• v.47 no.1
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• pp.82-85
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• 2010

Recently, thin film processes for oxides and metal deposition, such as physical vapor deposition (PVD) and chemical vapor deposition (CVD), have been widely adapted to fabricate solid oxide fuel cells (SOFCs). In this paper, we presented two research area of the use of such techniques. Gadolinium doped ceria (GDC) showed high ionic conductivity and could guarantee operation at low temperature. But the electron conductivity at low oxygen partial pressure and the weak mechanical property have been significant problems. To solve these issues, we coated GDC electrolyte with a nano scale yittria-doped stabilized zirconium (YSZ) layer via atomic layer deposition (ALD). We expected that the thin YSZ layer could have functions of electron blocking and preventing ceria from the reduction atmosphere. Yittria-doped barium zirconium (BYZ) has several orders higher proton conductivity than oxide ion conductor as YSZ and also has relatively high chemical stability. The fabrication processes of BYZ is very sophisticated, especially the synthesis of thin-film BYZ. We discussed the detailed fabrication processes of BYZ as well as the deposition of electrode. This paper discusses possible cell structure and process flow to accommodate such films.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.23 no.3
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• pp.206-210
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• 2010

$BaTiO_3$ dielectric ceramics are widely used to multi-layer ceramic capacitor. The $BaTiO_3$ powder was synthesized at $950^{\circ}C$ by using a solid state reaction and grinded by using a high-energy mill. And then, 2.53 wt% glass frit was added to the synthesized $BaTiO_3$ powders for lowering the sintering temperature. The mixed powders were sintered at various temperatures of $1170^{\circ}C$, $1200^{\circ}C$, $1230^{\circ}C$. Microstructures of the sintered $BaTiO_3$ ceramics were inspected by SEM and crystal structures were analyzed by XRD method. The relative dielectric constant was measured by using a impedance/gain phase analyzer. The synthesized $BaTiO_3$ powder had the tetragonal perovskite structure without secondary phase and the particle size was below 200 nm. The relative densities measured at the samples sintered at the temperature above $1200^{\circ}C$ were about 95%. The relative dielectric constant showed maximum value of 2310, which was measured in the specimen sintered at $1200^{\circ}C$. From these results, we could know that the added glass frit had effects on both lowering the sintering temperature and improving the dielectric property.

• Journal of the Microelectronics and Packaging Society
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• v.15 no.2
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• pp.55-61
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• 2008

This paper shows quantitative reliability evaluations of a Bluetooth module through extending previous qualitative methods limited to structure reliability tests and solder joint reliability tests for Bluetooth modules. Accelerated Life Testing (ALT) of the modules using temperature difference in temperature cycling as an accelerated stress was conducted for quantitative reliability evaluation under field environment conditions. Lifetime distribution parameters were estimated using the failure times obtained through the ALT, and then Coffin-Manson model was implemented. Results of the ALT showed that the failure mode of the modules was open and the failure mechanisms are both crack and delamination. The ALT reproduced the failure mode and mechanisms of failed Bluetooth modules collected from the field. Further, a quantitative reliability evaluation method with respect to various temperature differences in temperature cycling was proposed in this paper. $B_{10}$ lifetime of the module for the temperature difference $70^{\circ}C$ using the proposed method would be estimated as about 4 years.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.42 no.1
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• pp.91-97
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• 2005

In the mobile antenna systems for satellite multimedia communications, the active way antenna having a low sidelobe antenna pattern is described in this paper. This designed and fabricated array antenna is satisfied with international beam pattern regulation on moving states. The subarray of the proposed mobile antenna system is arranged with a stair-planar structure and non-periodic array spacing. This subarray is designed with three-layered microstrip patch as both receiving and transmitting radiator of which are improved with antenna gain and bandwidth. Also, the optimum subarray spacing is designed to make the lowest sidelobe pattern by genetic algorithm. In addition, the characteristics of a GA-perturbed array are investigated from simulated and measured beam pattern results.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.18 no.10
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• pp.1189-1195
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• 2007

We design and fabricate, in this parer, a triple band folded monopole antenna for the folder type mobile phone handset that can be served GSM/DCS/USPCS mobile phone system. Antenna structure is modified meander shape which is obtained both extension of antenna physical length for GSM band and same directional multi-currents flowing on the antenna conductor surface for DCS/USPCS band. This antenna has as good performances as high radiation resistance and gain increment, and would be applied to mobile phone handset that is not able to be performed by internal antenna. By measurement, fabricated antenna by the press process shows under VSWR 3:1 at closed folder state and 2:1 at opened folder state over whole GSM/DCS/USPCS band, and has maximum gain as -0.02 dBi for GSM, +0.2 dBi for DCS, +0.78 dBi for USPCS band with almost omnidirectional H-plane radiation pattern.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.26 no.9
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• pp.769-776
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• 2015

In this paper, a broadband MIMO antenna using the metal cover that is one of the antenna radiators is designed and implemented on the PCB. The proposed antenna consists of a monopole and an IFA fed by the coupling structure and a metal cover radiator. Therefore, a monopole and an IFA with a metal cover radiator operate simultaneously through a hybrid form of operation. The antenna satisfies VSWR 3:1 at the bands of LTE class 13, class 14, CDMA, GSM900, DCS, PCS, WCDMA, LTE class 40 and WiFi. The maximum ECC of diagonally fed MIMO antenna is 0.186. The measured average gain and efficiency were -5.14~-1.28 dBi and 30.87~74.48 % over the desire bands, respectively.

• International Journal of Human Ecology
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• v.2 no.1
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• pp.39-55
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• 2001

Concerns about paid-facilities for the elderly with dementia from middle and upper class families have been discussed lately in Korea. Small-scale, home-like group homes for the elderly with dementia were developed in Sweden in the 1980, but they have not been effectively introduced in Korea where they remain a comparatively new concept. The group home, however, would provide a good alternative to Koreans who feel guilty when they have to leave their frail parents in large-scale facilities or hospitals instead of caring for them at home. The aim of this paper is, first, to define the care of the demented elderly who come from upper and middle class families in Korea and, secondly, to discuss the need for group homes to help care for them. A survey was done by questionnaire and was answered by 577 respondents who belonged to middle and upper class families living in Korea in December 2000. Methods of analysis were frequency, mean, and Chi-square. The results of this study were as follows: 1) the traditional notion that the eldest son should be burdened with the primary responsibility for a demented parent has weakened remarkably; 2) a small-scale long-term care facility was considered the most desirable living environment for the demented elderly; 3) the facilities families needed for professional hospitals for victims of dementia, senior citizen centers, large and small-scale long-term care facilities, day-care centers, and short-stay and service housing. The study also revealed that there was low awareness of the group home. The most preferred type of structure for group homes was a single-family detached house, and the most preferred management system was small-scale that could create home-like atmosphere. Additionally the respondents wanted group homes to consist of 6-8 residents with 2-4 persons per room. The results of this study strongly suggest that policy makers should encourage the development of smallscale group homes as an alternative form of housing for the elderly with dementia.

• The Journal of the Korean bone and joint tumor society
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• v.9 no.2
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• pp.212-216
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• 2003

A Common peroneal nerve palsy caused by ganglionic cyst is very rare condition but well recognised entities. There have been three previous reports describing the magnetic resonance image (MRI) findings of peroneal nerve entrapment due to a ganglionic cyst. Ultrasonography, MRI, and electromyography (EMG), nerve conduction velocity (NCV), and microscopic examination were taken for diagnosis. A tubular structure near the fibular neck extending longitudinally over several slices with an inferior extension towards the superior tibiofibular joint with high T2 signal intensity was characteristic. The peroneal nerve was exposed and the ganglionic cyst was excised. The nerve was paralysed immediately after operation, but at 4 month after operation, started recovery of the function gradually and has recovered completely at 7 month. MRI is helpful to detect the extent, location, and origin of the cyst. Meticulous surgical excision can provide favorable result.

• Archives of Plastic Surgery
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• v.44 no.2
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• pp.95-100
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• 2017

Background Intima-to-intima microanastomotic vascular remodeling was explored, utilizing a polylactide-caprolactone absorbable vein coupler model (PAVCM), which was designed to simulate a non-absorbable counterpart system with the sole exception of being absorbable. Methods Six New Zealand white rabbits were used. After transection of the jugular vein, 2 PAVCMs were placed, 1 at each transected end. The stumps were slipped through the PAVCMs, and the venous wall was everted $90^{\circ}$ to achieve intima-to-intima contact. Reanastomosis of the transected jugular vein was performed bilaterally in 3 rabbits. In the other 3 rabbits, the jugular vein (20 mm) harvested from one side was interpositionally grafted to the jugular vein on the opposite side to ease the anastomotic tension. Patency testing, ultrasonography, and histologic assessments were conducted postoperatively at weeks 2, 4, 12, 16, 22, and 26. Results All anastomotic sites were patent, without stenosis, occlusion, or dilatation. In the histologic sections, immature endothelial regeneration was observed at week 2, which was completed by week 4. Regeneration of the tunica media was noted at week 12. Between week 22 and week 26, the tunica media fully regenerated and the coupler dissipated entirely. Conclusions Despite the absence of a coupler to act as an anastomotic buttress, the structure and function of all the vessels appeared normal, even histologically. These outcomes are true milestones in the development of an absorbable vein coupler.