• Journal of the Korean Society of Propulsion Engineers
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• v.15 no.4
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• pp.85-93
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• 2011

A parametric study is conducted for the design of segmented arc plasma torch with the input power and current of 0.4 MW and 300 A, respectively. For this purpose, we use the analytical relationship between input power, current condition, plasma temperature, inner diameter (R) and length (L) of the torch constrictor based on arc channel model. The results reveal that arc plasma temperatures increase monotonically as ��L increases or R decreases for the ranges of R ${\leq}$ 7.5 mm and L ${\leq}$ 1.25 m. For larger valuse of ��R and L than 7.5 mm and 1.25 m, respectively, however, they show non-linear behavior corresponding to the variations of ��L, which stands for the generation of unstable arc plasma. From this parametric study, optimum ranges of R and L are suggested as 5.5 mm ${\leq}$ R ${\leq}$ 7.5 mm and 0.25 m ${\leq}$ L ${\leq}$ 0.5 m for 0.4 MW class segmented arc plasma torch, under which stable arc plasma can be achieved at the input currents of ~300 A.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.40 no.3
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• pp.227-236
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• 2014

In this study, O/W and W/S emulsions were prepared by combining oils having different required hydrophilic lipophilic balance (HLB) values under the diverse conditions of HLB values composed of a hydrophilic surfactant and a lipophilic surfactant and their stability was investigated. Results showed that the higher the viscosity of O/W emulsions was as the lower the HLB value of emulsifier and emulsion particle showed a tendency to be a smaller and compact and stabler in centrifugal filtration. W/S emulsions also showed a similar tendency to be a smaller and compact as HLB values of emulsifier was higher and stabler in centrifugal filtration. However, the viscosity of W/S emulsion tended to get lower in HLB conditions of all emulsifiers as the time passed. This indicated that the emulsions had an unstable feature in long-term stability. In conclusion, the results showed opposite to the known theory that O/W emulsion is proper to be applied by nonionic surfactant with a high HLB value and W/S emulsion to be applied by nonionic surfactant with a low HLB value and provide useful information for the cosmetics research and related areas.

• Journal of KIISE:Computer Systems and Theory
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• v.28 no.9
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• pp.442-460
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• 2001

In video-on-demand(VOD) systems it is important to minimize initial latency and memory requirements. The minimization of initial latency enables the system to provide services with short response time, and the minimization of memory requirements enables the system to service more concurrent user requests with the same amount of memory. In VOD systems, since initial latency and memory requirement increase according to the increment of buffer size allocated to user requests, the buffer size allocated to user requests must be minimized. The existing static buffer allocation scheme, however, determines the buffer size based on the assumption that thy system is in fully loaded state. Thus, when the system is in partially loaded state, the scheme allocates user requests unnecessarily large buffers. This paper proposes a dynamics buffer allocation scheme that allocates user requests the minimum buffer size in fully loaded state as well as a partially loaded state. This scheme dynamically determines the buffer size based on the number of user requests in service and the number of user requests arriving while servicing current requests. In addition, through analyses and simulations, this paper validates that the dynamics buffer allocation outperforms the statics buffer allocation in initial latency and the number of concurrent user requests that can be supported. Our simulation results show that, in proportion to the static buffer allocation scheme, the dynamic buffer allocation scheme reduces the average initial latency by 29%~65%, and in a systems having several disks. increases the average number of concurrent user requests by 48%~68%. Our results show that the dynamic buffer allocation scheme significantly improves the performance and reduce the capacity requirements of VOD systems.

• Proceedings of the Korea Water Resources Association Conference
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• 2015.05a
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• pp.394-394
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• 2015

급격히 변화하고 있는 산업화와 도시화로 지구 온난화 현상으로 기상이변의 발생빈도가 높아졌고 기후가 불안정하여 예전보다 많은 집중호우가 발생하면서, 홍수로 인한 제내지 침수가 발생되기도 한다. 기후변화로 인한 수재해에 대응하기 위하여 하천 호소 수리 예측 모형의 개선이 필요한 실정이다. 하지만, 자연하천 유역의 강우-유출 상관관계와 지표면 유출현상 및 하도 수리 특성을 자연현상의 복잡성, 강우발생의 시간적 공간적인 발생과정의 임의성, 정확한 해석방법 및 확률 분석에 따르는 불확실성 들을 토대로 단순한 이론과 제한적인 경험공식 등에 의해서 해석, 재현 및 평가를 한다는 것은 매우 어려운 문제이다. 최근 IT 기술의 발전과 더불어, 많은 연구자, 엔지니어들이 기존 수리 수문학적 지식과 IT기술을 융합하여 복잡 다단한 수자원 환경 문제를 해결하고자 한다. 이와 같은 최근 연구 동향에 의거하여, 본 연구에서는 HEC-RAS, TELEMAC-2D 1, 2차원 수리 모형을 연계하여 하천 흐름 분석 및 홍수 범람 해석에 적용하였다. 본 연구에서는 HEC-RAS, TELEMAC 모형을 적용하여 2012년 태풍 '산바(SANBA)'로 인해 홍수 피해를 입은 고령군에 위치한 낙동강 본류 회천 유역(상류 회천교 ~ 하류 도진교)의 하도 내 흐름 분석과 하천 인근 제내지 홍수범람을 예측하였다. 범람해석에 필요한 지형자료를 기초로 하여 각 지형의 조건에 맞게 수치자료를 이용하여 작성하였고, 수자원 정보를 이용하여 유랑, 수위 등 시계열자료를 지류 및 상 하류의 경계조건으로 설정하고, 조도계수 등 하천 기본정보들을 입력하였다. HEC-RAS 모형은 회천교부터 도진교까지 전구간에 대한 종단면과 횡단면별 홍수침수범위 및 홍수위 크기 등 거시적인 1차원 수리해석에 적용하였고, TELEMAC 모형은 HEC-RAS 시뮬레이션 결과를 바탕으로 HEC-RAS에서 나타내기 힘든 2차원 흐름특성, 침수현상 등 일부 범람 구간에 대해 수리해석에 적용하였다. HEC-RAS 시스템은 수공구조물들의 영향과 하천의 영향을 종 횡단면으로 다양한 홍수침수 범위를 1차원으로 나타 낼 수 있으며, TELEMAC 시스템 수리 모의를 통해 얻어진 결과는 유속, 유량, 수심, 하상고 높이 등 2차원으로 나타낼 수 있다. TELEMAC 시스템을 활용한 2차원 분석은 실측자료와 비교적 유사하고 시각, 공간적으로 이해하기 쉽게 표현되므로, 모형 적용성이 우수한 것으로 판단된다. 향후 유역 해석을 위한 수치데이터, 수위, 유량자료를 확보하여 HEC-RAS, TELEMAC 1, 2차원 연계 모형을 적용 한다면, 하천 준설, 하천 구조물 설치, 홍수피해 등 전반적인 하천관리 계획에 활용할 수 있을 것이라 판단된다.

• Journal of the Korea Society of Computer and Information
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• v.25 no.6
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• pp.231-237
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• 2020

The purpose of this study is to present theoretical and policy implications based on the results of the empirical analysis of job stress in consideration of insufficient prior research on the level of job stress by public officials in charge of social welfare and public officials in general administration. For this purpose, social welfare and general administrative positions working at the City Hall of G Metropolitan City and five autonomous districts(including the Dong community service center) were selected as subjects for research. The data analysis used the SPSS statistical program to obtain technical statistics based on the average of the lower variables of the job stress. According to the analysis, there is a difference in the subjective perception level of public officials in charge of social welfare and public officials in general administration in both internal factors of job, such as job demands and job autonomy and external factors of job, such as job insecurity, organizational system, conflict of relations, inadequate compensation, and job culture. Based on this, it presented policy measures that require the granting of self-esteem of public officials in charge of social welfare, improvement of their duties, and adjustment of their workload to an appropriate level.

• Korean Journal of Labor Studies
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• v.24 no.3
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• pp.35-71
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• 2018

The purpose of this study is to examine which job-related factors are associated with presenteeism, which is defined as attending work while ill. Although presenteeism is a relatively new concept in academic research, it should be regarded as an important social issue in that presenteeism threatens employees' job prospects and quality of life as well as it causes loss of work productivity. I analyzed a cross-sectional survey of 24,571 wage workers over 15 from the fourth wave of the Korean Working Conditions Survey in 2014. Five logistic regression models were analyzed on experience of presenteeism, and work hours and private life, occupational environment, job insecurity, rewards and welfare were assessed as key predictors of presenteeism. I found that 1) work hours with bad fit with private life, 2) high level of work time-pressure, and low job satisfaction 3) job insecurity, and 4) low benefits are associated with experience of presenteeism. The findings are fairly consistent with the theory of job-person mismatch, which explains that workers tend to preserve their personal resources by going to work while ill (presenteeism) when job demands or work conditions do not match with their level of personal expectation and, thus, workers are afraid of loss of personal resources. Presenteeism influences worker's long-term health and quality of life negatively as well as causes serious social costs. Therefore, we need organizational efforts to prevent the negative effects of presenteeism on society as well as workers.

• 한국사회정책
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• v.25 no.1
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• pp.345-375
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• 2018

This study examines labour market and unemployment protection policies as a configuration in 12 OECD countries in order to investigate how countries from different regime conform to or diverse from previous welfare state regime discussion, and to examine its relationship with poverty and inequality. In analyzing the combination of the unemployment insurance, the unemployment assistance, and active labour market policy, firstly, fuzzy scores of unemployment insurance was calculated by analyzing the strictness of eligibility, duration of benefit and the generosity of income replacement rate. For unemployment assistance, the ratio of public assistance expenditure to the GDP in each country and the ratio of unemployment benefit level to the average wage in each country have been considered. As for the active labour market policy, the total expenditure per GDP of this policy was converted into fuzzy points and analyzed. As a result, 5 types in 2005 and 6 types in 2010 were generated. Specifically, 'assistance type(iAp)', 'insurance type (Iap)', 'comprehensive safety net type (IAP)', 'weak safety net type(iap)' were analyzed. This paper suggested policy implication for South Korean case, which consistently had high score for weak safety net type(iap).

• The Southeast Asian review
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• v.24 no.2
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• pp.167-206
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• 2014

메콩 경제권(GMS)의 다양한 개발 현장 속에서 고무 나무로부터 채취하는 라텍스는 캄보디아, 라오스를 포함한 인도 차이나 반도 국가들 사이에서 주요 농업 활동으로 주목 받고 있다. 그러나 캄보디아와 라오스의 대형 플랜테이션은 여러 부정적인 결과들을 낳고 있다. 토지 점유, 계약 농업을 통한 착취 등으로 인해 역설적으로 농촌의 빈곤은 증가하고 있고 해외 투자자에 대한 재정적, 기술적 의존이 심화되고 환경 파괴가 일어나고 있다. 이러한 점들로 인해 소규모 자작농들에 주목할 필요가 있다. 고무 자작농은 고용을 창출하며 토지 점유를 방지한다. 본 연구는 캄보디아와 라오스의 소규모 고무 자작농들의 생계를 비교하며 고무 호황으로 어떠한 이득을 얻고 어떠한 형태로 생계를 개선할 수 있는지를 연구한다. 본 연구는 캄보디아의 Tboung Khmum 구역과 Somsanouk 마을의 사례 연구를 바탕으로 하였다. 실증적인 분석은 세 가지의 이론적 틀을 바탕으로 하였다. 미시-생계 연구, 글로벌 가치사슬 그리고 GMS에 대한 연구들이다. 실증 분석의 초점은 생계의 변화상과 결과(고용 창출과 빈곤 탈출)이다. 전체적으로 소규모 고무 자작농은 전망이 밝았으나 앞서 언급 된 문제점들로 인해 농촌 문제를 모두 해결할 수 있는 수단은 아니다. 중요한 유사성은 소규모 고무 자작농의 사회경제적 공헌이다. 연구 지역 두 곳에서 자작농들은 고무 농사는 생계를 개선하는 데에 좋은 수단이라고 답하였다. 그럼에도 불구하고 낮은 교육 수준은 그들의 생계 전략을 불안정하게 하고 있다. 양쪽 지역에서 응답자들은 다른 주민을 따라 고무 농사를 시작했다고 대답했으며 경제, 환경적인 위험에 대해 충분히 인지하고 있지 못하였다. 이와 관련한 다른 유사점으로 소규모 자작농들을 지원할 수 있는 정부의 개입이 없었다는 것이다. 자금 조달은 고무 농사의 심각한 애로 사항 중 하나였다. 명확한 차이점으로 Tboung Khmum의 자작농들은 중개 상인에게 계약 관계를 맺지 않고 라텍스를 판매했으며 Somsanouk의 경우에는 고무 가격이 국제 시장의 영향을 받음에도 가장 높은 가격을 제시하는 상인에게 농민 전체가 같이 판매를 하였다. 이러한 현상은 GMS 내에서 이루어지고 있는 근대적인 경제 현상 에 농촌 공동체들이 다양하게 연결 되고 있음을 재확인한다. 게다가 Somsanouk 마을에서는 사이짓기를 하는 경우가 없었다. 이는 투자자들이 생산량을 극대화하기 위해 자작농들에게 사이짓기를 장려하지 않았기 때문이다. Tboung Khmum 마을의 경우 고무와 더불어 고무 이전의 주요 작물이던 카사바를 같이 재배했다. 요약하면, 자작농에 의한 소규모 고무농업은 (비록 농촌의 모든 어려움을 해결할 수는 없지만) 토지점유 등 부정적 현상이 나타나는 대규모 플렌테이션에 비해 유의미한 일자리를 창출하는 등 미래를 위한 보다 나은 대안이 될 수 있다. 농촌 생활의 질을 개선하기 위해서는 7년 간의 고무 생육기간 동안 농가가 감수해야 하는 사회-경제적 불안정성을 해결하고 대안적 소득원을 마련할 필요가 있다

• The Journal of the Korea Contents Association
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• v.21 no.7
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• pp.83-92
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• 2021

The goal of this paper is to explore the relationship between visual and auditive meanings of the film "The Imitation Game"(2013) which is directed by Morten Tyldum, and with music composed by Alexandre Desplat. The author accepted Zwikowski's idea of analyzing how film music and visual information created a chemical and meaningful signal for the audience. Lawrence Zbikowski has used Conceptual Integration Networks (CIN), devised by Golles Fauconnier and Mark Turner, to analyze latent meanings which was produced by the association of visual and auditive meanings. Therefore, The author applied the CIN analyzing methodology to the research combination of music and imagery in "The Imitaion Game." Desplat, the composer, has used aeolian instead of tonality to represent the main character. The aeolian melodic line was changed to create a similar atmosphere of imagery and narratives. The irregular time and minor chord was associated with unstable emotion and familiar intervals, while the major chord was associated with stable feelings. Desplat also applied instrumental diversity and extreme changes of dynamic to create positive or negative cognition. The author, therefore, found how the meanings of auditive materials and visual information combined and emphasized encoded messages in the film.

• Korean Journal of Ecology and Environment
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• v.34 no.1 s.93
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• pp.9-19
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• 2001

contrasting monsoon between 1993 and 1994 produced an interannual difference in hydrology. Theoretical water residence time (TWRT) in monsoon 1993 averaged 27 d, which was>3 months shorter compared to the TWRT in monsoon 1994. A dominant physical process influencing thermal stratification, water movement, and mixing regime was an interflow current in 1993. During summer 1993, river water plunged to mid-lake (location 27 km) and passed through the 10${\sim}$20m stratum of the reservoir, resulting in an isolation of epilimnetic lake water from advected river water. The interflow disrupted thermal stratification and produced a meta-hypolimnetic warming of >4$^{\circ}C$ downlake, thereby increased a mixing depth (>13 m). In contrast, during monsoon 1994 density currents were not observed and strong thermal stratification occurred in the entire reservoir, resulting in > 2 fold greater thermal resistance (8.2${\times}10^{5}$ erg)compared to 1993 (4.0${\times}10^{5}$ erg). This reservoir was identified as a typical warm monomictic reservoir which showed one mixis during early winter. The timing of overturn, however, differed between the two years as a result of distinct contrast in TWRT and thermal regime; overturn in 1993 occured about one month earlier relative to that in 1994. Hypolimnetic warming was predictable in this system; the variation in discharge accounted (Y = 4.35-0.06X+0.10X$^{2}$, p<0.0001)for 98% of the interannual variation in hypolimnetic temperature. Overall data suggest that thermal stability, the timing of fall overturn, and water residence time in this system are primarily regulated by the intensity of monsoon.