• Journal of Information Display
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• v.3 no.1
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• pp.6-10
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• 2002

We have synthesized a new green Ir(III) complex fac-tris-(3-methyl-2-phenyl pyridine)iridium(III) $Ir(mpp)_3$ and fabricated phosphorescent polymer light-emitting device using it as a triplet emissive dopant in PVK. $Ir(mpp)_3$ showed absorption centered at 388 nm corresponding to the $^1MLCT$ transition as .evidenced by its extinction coefficient of the order of $10^3{\cdot}$ From the PL and EL spectra of the $Ir(mpp)_3$ doped PVK film, the emission maximum was observed at 523 nm, due to the radiative decay from the $^3MLCT$ state to the ground state, confirming a complete energy transfer from PVK to $Ir(mpp)_3$. The methyl substitution has probably caused a red shift in the absorption and emission spectrum compared to $Ir(mpp)_3$. The device consisting of a 2 % doped PVK furnished 4.5 % external quantum efficiency at 72 $cd/m^2$ (current density of 0.45 $mA/cm^2$ and drive voltage of 13.9 V) and a peak luminance of 25,000 $cd/m^2$ at 23.4 V (494 $mA/cm^2$). This work demonstrates the impact of the presence of a methyl substituent at the 3-position of the pyridyl ring of 2-phenylpyridine on the photophysical and electroluminescence properties.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.6 no.8
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• pp.1200-1205
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• 2002

Construction of Private networks is becoming easier due to the openness of telecommunication market, rapidly developing telecommunication technology. The size of existing private networks is becoming huge which resulted in surplus of capacity of the networks. These trends will generate a problem of efficient use of national telecommunication resources and which will be a factor for the structure of domestic telecommunication market which will have a big impact on the existing telecommunication carriers. Therefore, national policy of private network issues should be considered along with the national efforts for the information infrastructure, control of telecommunication market, fairness of competition, strength Power of national competition. In this paper it will be suggested that the efficient policy on the issue of domestic private network, by analyzing present situation, status quo, laws, regulation and procedure for domestic private networks and comparing it with those of U.S.A, Japan, EU.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.27 no.1B
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• pp.24-33
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• 2002

The cell search scheme for W-CDMA consists of the following three stages: slot synchronization(1st stage), group identification and frame boundary detection(2nd stage), and long code identification(3rd stage). The performance of the cell search when a mobile station is switched on, which is referred to as initial cell search, is decreased by the initial frequency and timing error. In this paper, we propose the pipeline structured initial cell search scheme using time trackers to compensate for the impact of the initial timing error in the stage 2 and stage 3. The simulation results show that the performance of the proposed scheme is maximal 1.5dB better than that of the conventional one when the initial timing error is near ${\pm}T_c$/2.

• The Korean Journal of Financial Management
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• v.19 no.1
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• pp.153-181
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• 2002

본 논문은 1999년 1월부터 2000년 12월까지 코스닥증권시장에 등록한 벤처기업의 IPO를 대상으로 발행시장에서 벤처캐피탈리스트의 역할을 살펴보고 있다. 특히 미국의 발행시장에서는 벤처캐피탈리스트가 투자한 기업이 조기에 공개되는 현상이 나타나는 것으로 보고되고 있는 바, 우리나라에서도 이러한 현상이 존재하는지를 실증적으로 조사하고 있다. 코스닥증권시장에 등록한 벤처기업의 IPO를 대상으로 발행시장에서 벤처캐피탈리스트의 역할에 관한 우리의 연구 결과는 다음과 같다. 첫째, 벤처기업과 비벤처기업의 초기 초과수익률의 차이분석에서, 벤처기업은 $AR_1$에서 할인 발행의 정도가 적어 Megginson-Weiss(1991)의 결과와 유사한 것으로 나타났지만, $AR_2$에서 발행가격 결정시 고려하지 못하는 비계수적 환경요인 등 미래기대수익에 대한 일반투자자의 평가가 호의적으로 나타나 발행회사의 입장에서는 할인발행의 정도가 큰 것으로 나타났다. 이는 이기환 임병균 최해술(1998), 장상수 길재욱(2000) 등의 연구와 유사한 결과를 보이고 있다. 둘째, 벤처캐피탈리스트의 명성에 따라 초기 초과수익률에 차이가 있었다. 즉, KTB지원기업의 초기 초과수익률이 낮았다. 셋째, 벤처캐피탈리스트의 보유지분을 변동에 대한 차이는 IPO전 평균보유지분율은 비KTB가 높았으나 공개 후 평균보유지분율은 KTB가 높았다. 이때 보유지분을 변동이 적은 KTB 지원기업의 초기 초과수익률이 낮았다. 특히 업력과 총자산의 규모가 할인발행을 줄이는 역할을 하는 것으로 나타났다. 업력은 Muscarella-Vetsuypens(1989)의 연구와 일치하고 있다. 넷째, 2개 이상의 벤처캐피탈리스트로부터 공동으로 투자받은 벤처기업의 초기 초과수익률이 하나의 벤처캐피탈로부터 단독으로 투자받은 벤처기업의 초기 초과수익률보다 낮았다. 그러나 통계적 유의성은 없었다. 다섯째, IPO까지 소요기간의 차이가 있는지에 대한 분석에서 비KTB지원기업이 보다 빨리 공개되고 있어 조기업적과시현상(grandstanding)을 보였다. 이는 Gompers(1996)의 연구와 일치한다. 여섯째, 등록주선인의 시장점유율에 차이가 있는지를 분석한 결과, KTB가 투자한 벤처기업 등록주선인의 평균시장점유율이 낮았다. 그러나 통계적 유의성은 없었다.

• Child Health Nursing Research
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• v.10 no.2
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• pp.143-152
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• 2004

The purpose of this study was to examine to what extent teenagers accepted sexual relations, and to determine in which way that was affected by their disposition of stimuli, one of the psychological factors, and by their adjustment to school life, one of the environmental factors, as those factors seemed to have impact on that. This study was of descriptive correlational approach, and the subjects were 962 boy and girl students randomly selected from regular and business high schools. The data were collected from May through July 2002, and SPSS win 10.0 program was employed for data analysis. The major findings of this study were as follows; First, the students investigated got a mean of 44.49 marks on school adjustment. Their sensation seeking got an average of 130.10 marks. Their sexual allowance got a mean of 38.90 marks. Second is to regard the influence of their general characteristics on school adjustment, sensation seeking and sexual allowance. school adjustment was significant on gender, grade, career track, religion, school record, economic state, sexual intercourse. Sensation seeking was significant on all of their general characteristics. Sexual allowance was significant on all except economic state. Third, concerning correlation among sexual allowance, school adjustment and sensation seeking, sexual allowance was positively correlated to sensation seeking and negatively to school adjustment. The above-mentioned findings suggested that school adjustment and stimuli pursuit was associated with sexual attitude, and the findings of this study are expected to make any contribution to creating an ideal sexual culture for the youth.

• Proceedings of the Korean Environmental Health Society Conference
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• 2002.04a
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• pp.91-99
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• 2002

A recent survey investigated that there were over one thousand un-controlled closed landfills(1,072 sites) in Republic of Korea. Most of these landfills were constructed before 1986. Waste management act were not promulgated at that time, so they usually do not have dranage system and leachate treatment facility. Also, considerable attention has been received to landfill leachate pollution, leachate has an adverse impact on the surrounding environment such as soil, groundwater, and water supply source. According to the result of survey for closed landfill management, it was reported that 875 sites out of 1,072sites(81.6％) have no leachate treatment facility and 630 sites out of 1,072sites(58.7％) have been used for farm lands and residence. Consequently it is hard to do postclosure care continuously in most of cases and these uncontrolled landfills have contaminated farm lands and residence. The average age of these landfills are ranged mostly between 2 to 15 years. Much time and advanced technology are needed to remediate these uncontrolled landfills, therefore the survey for present status of closed landfill sites is required and suitable treatment processes should be prepared. With this point of view, We has been investigated to find out the present status of closed landfill, problems of post management and discussed plans for remediation and reuse. Remedial actions of un-controlled landfill have been carried out the many cities since 1997 upto now. Most frequently applied technology were reuse after excavation and there were several cases to capping in the surface of landfill and to construct subsurface barriers. It is considered that landfills in use have a possibility not to be controlled because of inadequate construction and improper management. Therefore remediation of uncontrolled landfills and recovery technology should be develop continuously Especially, it has been expected that resource technology of landfill gas as a energy has some advantages in controlling odors in the site area and accelerating stabilization of landfills with the energy.

• Journal of Environmental Health Sciences
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• v.33 no.6
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• pp.479-487
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• 2007

[ $PM_{2.5}$ ], particulate matter less than 2.5 um in a diameter, can penetrate deeply into the lungs. Exposure to $PM_{2.5}$ has been associated with increased hospital visits for respiratory aliments as well as increase mortality. $PM_{2.5}$ is a byproduct of combustion processes and as such has a complex composition including a variety of metallic elements, inorganic and organic compounds as well as biogenic materials (microorganisms, proteins, etc). In this study, the average concentrations of fine particulates $PM_{2.5}$ have been measured simultaneously in Asan and Seoul, Korea, by using particulate matter portable sampler from September 2001 to August 2002. Sample collection filters were analyzed by ICP-OES to determine the concentrations of metallic elements (As, Ni, Fe, Cr, Cd, Cu, Pb, Zn, Si). Annual mean $PM_{2.5}$ concentrations in Asan and Seoul were 37.70 and $45.83\;{\mu}g/m^3$, respectively. The highest concentrations of $PM_{2.5}$ were found in spring season in both cities and the concentrations of measured metallic elements except As in Asan were higher than those in Seoul, suggesting that yellow dust in spring could affect $PM_{2.5}$ concentrations in Asan rather than Seoul. The correlation coefficients of Pb and Zn were 0.343 for Asan and 0.813 for Seoul during non-yellow dust condition, suggesting that Pb and Zn were influenced with the same sources. The correlation coefficients between Si and Fe in the fine particulate mode were 0.999 (Asan) and 0.998 (Seoul) during yellow dust condition. It was suggested that these two elements were impacted by soil-related transport from China during the yellow dust storm condition.

• The Journal of Korean Medicine
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• v.35 no.1
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• pp.145-156
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• 2014

Objectives: Korean medicine hospitals, since they first emerged in the early 1970s, have rapidly become a new member of the hospital population. As it was a new organizational frame for traditional medicine, we tried to analyze the changes of Korean medicine hospitals coping with institutional environment and their relative positioning in the whole health care sector. Methods: On the basis of Scott and his colleagues' identification of the three components of institutional environments, changes in organizational logics, actors, and governance of Korean medicine hospitals during the period from 1971 to 2010 were analyzed. Results: First, Similar to previous literature on institutional eras of Korean health sector, three distinct periods were characterized: the foundation of Korean medicine hospitals to consolidate the legal status(1971~1986), a rapid increase of entrepreneurial hospitals through cultural-cognitive legitimacy(1987~2001), and the reinforcement of specialization and competition(2002~present). Conclusions: Results suggested that: (1) changes in institutional environments hada heavy impact on structural and behavioral changes among Korean medicine hospitals, but the pace was slower than that of western medicine hospitals. (2) In structure, Korean medicine hospitals have positioned themselves as unofficial long-term care hospitals, focusing on chronic diseases(e.g. cerebrovascular disease). Our study demonstrated that organizational theories can provide useful framework for the analysis of Korean medicine and related policies. Indeed, one of the most important implications of this study is that understanding changes in institutional environments is important to understand the process of how members of the health care sector live, grow, change, decline and survive.

• Proceedings of the KSME Conference
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• 2002.08a
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• pp.739-742
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• 2002

The supersonic, dual, coaxial jet impinging upon a vertical flat plate has recently been applied to a variety of industrial manufacturing processes, since it has several advantages over a conventional supersonic impinging jet. In the present study, experimentation is carried out to investigate the effects of the impinging angle of the annular flow and the design Mach number on the flow field formed over the vertical flat plate. A convergent-divergent nozzle is used to obtain the inner jet flow, its design Mach number being changed between $1.0\;and\;2.0$. The outer annular nozzle has a constant area of the Mach number of 1.0, and its impinging angle of $0^{\circ}\;and\;20^{\circ}$. The primary jet pressure ratio is changed in the range from 6.0 to 10.0 and for the annular flow, the assistant jet pressure ratio is changed from 1.0 to 4.0. The distance between the dual, coaxial nozzle and flat plate is also changed. Detailed pressure measurements are conducted along the axis of the jet and on the flat plate as well. The impinging coaxial Jet flows are visualized using the Schlieren and Shadow optical methods. The results show that the flow field on the plate is not strongly dependent only on the primary and assistant pressure ratios but also the impinging angle of the annular nozzle.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.18
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• pp.7929-7934
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• 2014

Background: The primary objective of this study was to assess the proportion of malignancies in ovarian masses during $1^{st}$ January 2002, to $31^{st}$ December 2011 at the Department of Obstetrics and Gynecology, King Chulalongkorn Memorial Hospital. A secondary objective was to evaluate associations with patients' clinical characteristics and ovarian malignancy proportion and subtypes. Materials and Methods: Retrospective descriptive study analyzed data of ovarian masses larger than 3 centimeters in maximal diameter, from the division of Gynecologic Cyto-Pathology at KCMH. SPSS software version 17 (SPSS, Inc, Chicago, IL, USA) was used. Results: A total number of 6,115 patients were included. Among the total ovarian masses studied, 13.7% were malignant. After the age of sixty, the proportion reached almost 40%. It was also above 20% in women younger than 20 years old. During premenarche period, proportion of ovarian malignancies was 50%. Only 1% of ovarian masses were found to be malignant during the pregnancy and post-partum periods. Parity decreased the probability of ovarian malignancy during postmenopausal years. Period of menopause did not have any impact on this probability. During the first two decades of life, germ cell malignancy dominated. As the age increased, the percentage of surface epithelial-stromal malignancy increased with a peak at the fifth decade. In contrast, malignant sex cord-stromal cell tumors occurred at a constant rate in each age group after the thirties. Conclusions: Proportion of ovarian cancers in each age group, menstrual and pregnancy status are similar. However there are differences in the distribution of ovarian subtypes especially for the surface epithelial-stromal category.