• Korean Journal of Materials Research
• /
• v.6 no.4
• /
• pp.349-356
• /
• 1996

완화형 강유전체의 가장 대표적인 PMN계에서 첨가제의 종류와 함량, 측정온도, 인가 전계의형태 등의 변화에 따른 전계인가 변화특성을 광법위하게 조사하였다. Columbite precursor법에의해 분말을 준비하고 고상소결방법에 의하여 모든 시편을 제조하였다. 순수한 PMN에 첨가제로서 PbTiO3와 Pb(Zr, Ti)O3를 첨가한 경우에 완전한 perovskite 구조의 고용체가 형성되었음을 알 수 있었다. T$\varepsilon$max이상에서는 변위의 이력이 크게 발생하는 강유전체의 거동을 보여주었다. 양방향으로 전계를 인가하여 변위를 이용하면 발생 strain은 실온 근방에서 온도에 대하여 안정적이지만 단방향 전계에 따른 변위는 온도에 따라 크기가 변한다는 것을 알 수 있었고 유전상수가 큰 경우가 전왜의 크기 또한 큰 것을 알 수 있었다. 0.9MN-0.1PT와 0.8PMN-0.2PZT의 경우 최대가 되는 온도는 유전율이 최대가 되는 온도보다 더 낮은 온도에서 나타났다.

• Proceedings of the KIPE Conference
• /
• 2020.08a
• /
• pp.407-408
• /
• 2020

본 논문은 SiC-MOSFET 기반 전기차용 인버터의 DC-Link 캐패시터 전기용량을 선정하는 방법에 대해 연구하였다. 인버터 시스템에 주로 사용되는 DC-Link 캐패시터는 안정적인 전원 및 고주파 전류 공급 등의 중요한 역할을 한다. 그러나 인버터가 고용량일수록 캐패시터 사이즈가 커지고 무게가 늘어나는 문제가 발생한다. 따라서, 차세대 전력 반도체 소자로 각광 받는 SiC-MOSFET의 높은 동작 주파수의 특성을 활용하여 캐패시터 소형화를 실현시켰다. 또한, PSIM 시뮬레이션을 통해 제안하는 연구의 타당성을 검증하고 Si-IGBT 인버터와 비교하여 그 효과를 입증하였다.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
• /
• 2022.11a
• /
• pp.99-100
• /
• 2022

자율운항 및 무인선 등 새로운 선박의 도입을 위한 기술개발과 함께 선박중심직접통신(M-S2X)의 필요성이 확대되고 있으며, 고용량, 고속의 서비스 구현을 위해 광대역 기반의 선박중심직접통신(Mx-S2X) 기술개발이 진행되고 있다. Mx-S2X의 안정적 서비스 구현을 위해 활용 가능한 주파수를 탐색하고 적정 주파수를 식별하고자 한다.

• Proceedings of the Korea Information Processing Society Conference
• /
• 2008.11a
• /
• pp.1079-1082
• /
• 2008

최근의 모바일 장치는 많은 발전을 이루어 과거에 비해 하드웨어 성능은 비약적인 발전을 이루며 다양한 모바일 장치로 발전하였다. 이와 함께 모바일 네트워크 환경도 많은 발전을 이루어 모바일 상에서도 고용량의 데이터를 고속으로 전달할 수 있는 환경이 가능해 졌다. 이처럼 발전된 모바일 환경에서도 여전히 서버 의존적인 시스템은 서버에 많은 부하를 줄 수밖에 없었다. 여기에 사용자의 환경에 맞는 서비스를 제공하기 위해서는 실시간으로 변하는 사용자의 정보를 지속적으로 서버에 전달해야 하기 때문에 이러한 과정에서 많은 오버헤드가 발생하였다. 고도로 발전된 모바일 환경에서 클라이언트 자신 스스로가 사용자의 실시간으로 변화하는 정보에 맞추어 최적화할 수 있는 시스템은 서버에 대한 의존도를 낮출 수 있어 더욱 빠르고 안정적이며 보안성을 높인 서비스가 가능하다. 본 논문은 이와 같은 클라이언트 중심의 비디오 서비스 전달 시스템을 위한 C3DS(Client Centeric Contents Delivery System)을 제안하고자 한다.

• Culinary science and hospitality research
• /
• v.19 no.3
• /
• pp.1-17
• /
• 2013

This research was to examine the effects of downsizing kitchen employees in a hotel on their job efficiency and to verify differences in the individuals' behavior characteristics according to DISC behavior types in this causal relationship. Through SPSS 17.0 program, factor analysis, reliability analysis, correlation analysis, and multiple regression analysis were conducted on 200 samples secured for an empirical research. Two factors for the downsizing items and two factors for the items related to job attitude were extracted. Hypothesis 1 was that the downsizing within a hotel has significant negative (-) effects on job attitude. As a result of the verification, it was found that downsizing had significantly negative effects on the job attitude of cooking employees as factors for organizational commitment in employment circumstances (${\beta}$=-.256), and employment anxiety (${\beta}$=-.258), and as factors for job satisfaction in employment circumstances (${\beta}$=-.319), and employment anxiety (${\beta}$=-.174). Hypothesis 2 was that the downsizing according to DISC behavior types has significant negative (-) effects on job attitude. As a result of the verification, it was found that in the organizational commitment factors, the dominance type (D) was more influenced by employment anxiety (${\beta}$=-.435) than by any other types, and the conscientiousness type (C) was not influenced by organizational commitment. In the job satisfaction factors, the steadiness type (S) was more influenced by the changes in employment circumstances (${\beta}$=-.414) than by other types, and the dominance type (D) was not influenced. Based on the results of this research, it can be said that hotel's downsizing strategies influence job attitude such as organizational commitment and job satisfaction of cooking employees, and that there are differences in the influences according to the individuals' behavior types of kitchen employees.

• Journal of Labour Economics
• /
• v.25 no.1
• /
• pp.131-160
• /
• 2002

This article tried to find out the individual wage effect of training. This Article used 1998, 1999 KLIPS(Korea Labor and Income Panel Study) panel data. The size of the individual wage effect of training was twice of tenure's, and had significance. Training had a good effect on the job satisfaction and carrier development. To overcome self selection bias, this article regressed the first difference of wage equations, but we didn't get the significant results. Dividing sample into quitters and non-quitters in order to investigate the relation between training cost and benefit, we regressed separately the each first difference of wage equation. On quitters, the individual effect of training appeared significantly, but on non-quitters, it didn't. This results mean that employer does not raise wage rate according to upgraded skill originated in incumbent's training. And the results also mean that the upgraded skill of employee who quit pre-employer is recognized by new employer, and his wage rate rises in his new job.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.19 no.5
• /
• pp.244-252
• /
• 2018

This study examined the aging of people with severe disabilities experiencing relative alienation and deprivation in an aging society to find ways to make them happy and economically stable. This study identified the determinants of economic preparation for aging among people with severe disabilities using the ecosystem perspective. For this study, data were drawn from Panel Survey of Employment for the Disabled (PSED). A total of 950 samples were used from the eighth wave. Logistic regression analysis was conducted to examine the influence of various factors. As a result, age, level of education, employment, subjective socioeconomic status, self-esteem, income, homeowner, and non-beneficiaries affected the economic preparation for aging. These findings have practical and political implications concerned with improving the economic preparations for aging among people with severe disabilities.

• The Korean Journal of Applied Statistics
• /
• v.27 no.3
• /
• pp.387-396
• /
• 2014

The GDP gap (also called the output gap) is the difference between potential GDP and actual GDP. Potential GDP is the maximum sustainable output that is achieved when the resources (labor and capital) are used to capacity. Central banks pursuing price and employment stability consider the output gap as an informative variable for monetary policy since the output gap could be regarded as a proxy of demand-supply imbalances. In this paper, the GDP gap of Korea is decomposed following the filtering method in the previous research, and major factors that affect the variation of GDP gap are investigated based on the decomposed series. The analysis results by the Super Smoother algorithm used in Fox et al. (2003)and Fox and Zurlinden (2006) are found consistent with theory. Much of the variation of nominal GDP gap is explained by Total Factor Productivity(TFP) gap, which is the change of productivity due to recent technological innovation and environmental change. It is also found that variation of terms of trade significantly affects the GDP gap of Korea due to its high dependency on international trade; however, the effect of the domestic price is not negligible like other countries.

• Journal of the Korea Safety Management & Science
• /
• v.16 no.1
• /
• pp.53-68
• /
• 2014

The purpose of this study is to verify the relationships among innovative behavior, turnover intention, and job security. An additional purpose was to examine partial mediating effects on psychological ownership. The baseline of analyzing those relationships in this study is that the role of psychological ownership will be a mediator between job security and turnover intention as well as innovative behavior in the organization. To accomplish these purposes, a model was built among job security as predictor variable, the psychological ownership as mediating variable and turnover intention, and innovative behavior as criteria variables based on the studies conducted in the various areas. The 248 questionnaires surveyed from the area of DaeGu and Kyungbuk were used in the statistical analyses. The detail statistical techniques are such as descriptive analysis, reliability analysis, factor analysis, correlation analysis, and multi regression analysis. The results of the study show that job security had positively significant effect on turnover intention and innovative behavior. In addition, only the psychological ownership of organization-level thinking have partial mediating effects between job security and innovative behavior also job security and turnover intention. The results may indicate that the psychological ownership of organization-level thinking be a key factor to alleviate the turnover intention of employees and to encourage the innovative behavior during their works for the small-medium size companies showing the unstable job security.

• Journal of Labour Economics
• /
• v.30 no.1
• /
• pp.109-137
• /
• 2007

One of the key features of the Korean labor market is that, even though the central axis of employment has shifted from manufacturing sector to service sector, the ratio of part-time work is very low. Its major reasons are low wage rate, insufficient fringe benefits including social insurance, and deficient job security, even though part-time work has positive characteristics. This study examines whether part-time work would be a decent one and an alternative to full-time work by answering two questions: one is who chooses part-time work and another is whether part-time work is satisfactory. Analyses of 3,971 wage workers in the 8th wave of the Korea Labor and Income Panel Survey reveal that, as expected, part-time work is prevalent among the young, married women, and the old supporting the results from previous studies and that choosing part-time work on one's initiatives has a significant positive effect on job satisfaction for women while it is not for men. Form the result, it can be concluded that part-time work can be an appropriate alternative for full-time work if one chooses it voluntarily.