• 벤처창업연구
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• 제13권6호
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• pp.117-127
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• 2018

본 연구에서는 개인이 새로운 문제해결을 시도하는 상황에서 개인의 기업가지향성과 문제해결전략이 어떠한 상호작용을 일으키는 지에 대해 분석하였다. 대한민국 국민 10,000명을 대상으로 하는 기업가정신실태조사의 설문 조사 결과를 토대로, 기업가지향성의 세 가지 차원에 해당하는 혁신성, 위험감수, 그리고 진취성은 개인이 새로운 문제를 시도하는 경향에 긍정적인 영향을 미치는 것을 보였다. 서로 상반되는 두 가지의 문제해결전략으로 어려움에 부딪혔을 때 기존의 계획을 고수하며 어려움을 극복하기 위해 노력하는 끈기의 전략과, 이와 반대로 신속히 어려움에 대응하여 기존의 계획을 수정하고 재정립하는 전환의 전략을 측정하여, 이러한 상반된 전략이 개인의 기업가지향성과 새로운 문제에 시도하는 경향성 간의 상관관계에 어떤 조절효과를 미치는 지를 분석하였다. 분석 결과, 끈기의 문제해결전략은 혁신적인 개인이 새로운 문제를 시도하는 경향을 강화시키는데 반해, 위험을 감수하는 성향의 개인이 새로운 문제를 시도하는 경향은 약화시키는 것으로 나타났다. 전환의 문제해결전략은 진취적인 개인이 새로운 문제를 시도하는 경향을 강화시키는 것으로 분석되었다. 이러한 연구 결과는 서로 상반되는 접근방식인 끈기와 전환의 문제해결전략이 일반적이고 보편적인 상황에서의 개인이 새로운 문제를 시도하는 데에 기업가 지향성과 더불어 각각 서로 다른 상호작용을 보이는 것을 실증적으로 제시한 것으로, 선행연구에서 주로 제시되었던 기업가지향성의 성과를 확장하여 새로운 문제를 시도하는 일반적인 맥락을 추가하였다. 이와 본 연구에서는 더불어 대규모의 설문 조사 결과를 토대로 일반적인 문제해결 맥락에서의 전략적 접근 방식이 새로운 문제를 시도하는 데에 미치는 영향을 실증적으로 분석하여, 선행연구에서 대규모 자료 수집의 어려움으로 인해 실증연구 결과가 미흡하였던 부분을 밝히는 데 공헌하였다.

• 산학경영연구
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• 제1권
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• pp.115-134
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• 1987

The increased number of organized employees and amount of collective bargaining in the public sector has caused many industrial relations students to pay attention to the compulsory arbitration mechanism. Some of these have criticized the compulsory arbitration on the grounds that it tends to replace collective bargain ing itself. They argue that each party lacks the incentive to concede and compromise that is so necessary in reaching agreements as long as the threat and/or use of strike is unavailable to them. On the other hand, the proponents of the compulsory arbitration maintain that compulsory arbitration carries out a strike like function by imposing the cost of disagreement. This paper is primarily concerned with these contradictory issues. More particularly, an attempt is made to analyze the impact of the compulsory arbitration mechanism upon the collective bargaining process by developing a bargaining model with explicit considerations of the determinants of the concession behavior of each party as a function of the cost of disagreement and the risk willingness relationship between the parties. The analysis in this paper leads to a synthesis of the above competing arguments, and shows that those contradictory views on the effect of the compulsory arbitration are mainly due to their failure to con sider the concession process.

• ETRI Journal
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• 제27권6호
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• pp.747-758
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• 2005

The problem of selection among competing models has been a fundamental issue in statistical data analysis. Good fits to data can be misleading since they can result from properties of the model that have nothing to do with it being a close approximation to the source distribution of interest (for example, overfitting). In this study we focus on the preference among models from a family of polynomial regressors. Three decades of research has spawned a number of plausible techniques for the selection of models, namely, Akaike's Finite Prediction Error (FPE) and Information Criterion (AIC), Schwartz's criterion (SCH), Generalized Cross Validation (GCV), Wallace's Minimum Message Length (MML), Minimum Description Length (MDL), and Vapnik's Structural Risk Minimization (SRM). The fundamental similarity between all these principles is their attempt to define an appropriate balance between the complexity of models and their ability to explain the data. This paper presents an empirical study of the above principles in the context of model selection, where the models under consideration are univariate polynomials. The paper includes a detailed empirical evaluation of the model selection methods on six target functions, with varying sample sizes and added Gaussian noise. The results from the study appear to provide strong evidence in support of the MML- and SRM- based methods over the other standard approaches (FPE, AIC, SCH and GCV).

• 대한산업공학회지
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• 제21권4호
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• pp.609-628
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• 1995

This paper presents a reliability model and a data-analytic procedure for a repairable unit subject to failures due to multiple non-identifiable causes. We regard a failure cause as a state and assume the life distribution for each cause to be exponential. Then we represent the dependency among the causes by a Markov switching model(MSM) and estimate the transition probabilities and failure rates by maximum likelihood(ML) method. The failure data are incomplete due to masked causes of failures. We propose a specific version of EM(expectation and maximization) algorithm for finding maximum likelihood estimator(MLE) under this situation. We also develop statistical procedures for determining the number of significant states and for testing independency between state transitions. Our model requires only the successive failure times of a unit to perform the statistical analysis. It works well even when the causes of failures are fully masked, which overcomes the major deficiency of competing risk models. It does not require the assumption of stationarity or independency which is essential in mixture models. The stationary probabilities of states can be easily calculated from the transition probabilities estimated in our model, so it covers mixture models in general. The results of simulations show the consistency of estimation and accuracy gradually increasing according to the difference of failure rates and the frequency of transitions among the states.

• Journal of Electrical Engineering and Technology
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• 제9권3호
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• pp.957-963
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• 2014

Converter transformers play important roles in high-voltage direct current transmission systems. This paper presents experimental and analysis results of the combined electrical and thermal aging of oil-impregnated paper at pulsating DC voltages. Breakdown voltages and time-to-breakdown of oil-paper specimens were measured by using short-time and constant-stress tests. The breakdown characteristics of combined electrical and thermal aging on insulation system were discussed. According to the relationship between failure time and aging temperature, the two-parameter Weibull model was improved. On the basis of the competing risk algorithm and the improved Weibull model, the two factors failure model was calculated. And the influence of temperature in the insulation system has been analyzed. This model performs better than the two-parameter Weibull model when both time and temperature are considered as variables in estimating the lifetime of oil-paper insulation.

• 펄프종이기술
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• 제32권5호
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• pp.67-71
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• 2000

The history of the paper industry has shown a strong technological evolution which has been an essential factor in achieving low cost, high quality paper products and in sustaining the strength of the industry. In the last decades paper machine development has been rapid. This has helped to establish paper as a "low cost" material. In future, the pressure from the competing media will only accelerate the technological efforts to improve cost and functional'||'&'||'not;ity of paper. In addition, in the future, technological advances will be combined with innovation in busi'||'&'||'not;ness concepts. Certain production methods are likely to be developed which will distribute current process stages outside the paper mill. Papermakers can begin to reduce their invest'||'&'||'not;ment risk by subcontracting large-scale base paper production but taking responsibility for the higher value finishing process stages. Finishing will be more closely integrated with the final use. The role of technology supplier to the paper industry will naturally evolve to reflect all these changes. Metso is already actively collaborating downstream in the different paper-related business chains. This collaboration will be crucial for implementation of new business and technology innovations in P'||'&'||'P industry and Metso will certainly benefit from its catalyst role in this transition.

• 응용통계연구
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• 제35권1호
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• pp.35-47
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• 2022

Receiver operating characteristic (ROC) 곡선은 이항 반응 자료에 대한 마커의 분류 예측력을 측정하기 위해 널리 적용되어왔으며 최근에는 생존 분석에서도 매우 중요한 역할을 하고 있다. 여러 가지 유형의 중도 절단과 원인 불명 등 다양한 종류의 결측 자료를 포함한 생존 자료 분석에서 마커의 사건 발생 여부에 대한 예측력을 판단하기 위해 기존의 통계량을 확장하였다. 생존 분석 자료는 각 시점에서의 사건 발생 여부로 이해할 수 있으며, 따라서 시점마다 ROC 곡선과 AUC를 구할 수 있다. 본 논문에서는 우중도 절단과 경쟁 위험 모형하에서 사용되는 다양한 방법론과 관련 R 패키지를 소개하고 각 방법의 특성을 설명하고 비교하였으며 이를 검토하기 위해 간단한 모의실험을 시행하였다. 또한, 프랑스에서 수집된 치매 자료의 마커 분석을 시행하였다.

• 대한지리학회지
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• 제51권2호
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• pp.283-303
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• 2016

울리히 벡(Ulrich Beck)의 위험사회 개념은 위험을 둘러싼 공간적인 감수성이 부족하면서 특정 위험이 발생하고, 전개되고, 다면적으로 인지되는 역동적인 측면들이 누락되는 한계를 지니고 있다. 이에 대한 대안적 접근으로 벡의 위험사회론을 공간적으로 발전시킨 데틀레프 뮐러만(Detlef $M{\ddot{u}}ller$-Mahn)의 위험경관(riskscape) 개념을 소개하고, 이 개념을 동아시아의 맥락에서 이론화를 시도한다. 동아시아 발전주의 국가론의 핵심적인 전제는 적극적인 '국가의 역할(the role of the state)'을 주문한다는 점이다. 하지만 동아시아의 경제성장 및 근대화 과정에서 국가의 역할이 두드러졌다는 사실은 벡의 용어를 빌리자면 경제성장과 근대화의 댓가로 원자력 발전소와 같은 '만들어진 위험들(manufactured risks)'의 형성에 국가가 깊숙이 연루되었음을 의미한다. 따라서 동아시아 근대화와 위험사회화를 이해하기 위해서는 국가에 대한 분석이 긴요하다. 보다 구체적으로, 한국의 원전입지정책을 사례로 1) 단기간에 동아시아 경제성장을 효과적으로 추진하기 위하여 지배적 사회세력이 지역의 위험은 축소하고, 경제성장의 가치를 지역의 위험보다 우선시하는 국가적 차원의 위험경관을 형성하였음을 밝히고, 2) 또한 다양한 우발적 계기들(정치적 민주화 혹은 대규모 재난의 발생 등)에 의하여 다른 사회세력들이 생산한 위험경관들이 기존의 국가적 차원의 위험경관과 대립할 수 있음을 확인한다.

• Asian Pacific Journal of Cancer Prevention
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• 제14권9호
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• pp.5355-5360
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• 2013

Background: Clarifying the prognostic impact of histological type is an essential issue that may influence the treatment and follow-up planning of newly diagnosed cervical cancer cases. This study aimed to evaluate the prognostic impact of histological type on survival and mortality in patients with cervical squamous cell carcinoma (SCC), adenocarcinoma (ADC) and small cell neuroendocrine carcinoma (SNEC). Materials and Methods: All patients with cervical cancer diagnosed and treated at Chiang Mai University Hospital between January 1995 and October 2011 were eligible. We included all patients with SNEC and a random weighted sample of patients with SCC and ADC. We used competing-risks regression analysis to evaluate the association between histological type and cancer-specific survival and mortality. Results: Of all 2,108 patients, 1,632 (77.4%) had SCC, 346 (16.4%) had ADC and 130 (6.2%) had SNEC. Overall, five-year cancer-specific survival was 60.0%, 54.7%, and 48.4% in patients with SCC, ADC and SNEC, respectively. After adjusting for other clinical and pathological factors, patients with SNEC and ADC had higher risk of cancer-related death compared with SCC patients (hazard ratio [HR] 2.6; 95% CI, 1.9-3.5 and HR 1.3; 95% CI, 1.1-1.5, respectively). Patients with SNEC were younger and had higher risk of cancer-related death in both early and advanced stages compared with SCC patients (HR 4.9; 95% CI, 2.7-9.1 and HR 2.5; 95% CI, 1.7-3.5, respectively). Those with advanced-stage ADC had a greater risk of cancer-related death (HR 1.4; 95% CI, 1.2-1.7) compared with those with advanced-stage SCC, while no significant difference was observed in patients with early stage lesions. Conclusion: Histological type is an important prognostic factor among patients with cervical cancer in Thailand. Though patients with SNEC were younger and more often had a diagnosis of early stage compared with ADC and SCC, SNEC was associated with poorest survival. ADC was associated with poorer survival compared with SCC in advanced stages, while no difference was observed at early stages. Further tailored treatment-strategies and follow-up planning among patients with different histological types should be considered.

• Korean Journal of Radiology
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• 제22권12호
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• pp.1985-1995
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• 2021

Objective: Although the liver-to-spleen volume ratio (LSVR) based on CT reflects portal hypertension, its prognostic role in cirrhotic patients has not been proven. We evaluated the utility of LSVR, automatically measured from CT images using a deep learning algorithm, as a predictor of hepatic decompensation and transplantation-free survival in patients with hepatitis B viral (HBV)-compensated cirrhosis. Materials and Methods: A deep learning algorithm was used to measure the LSVR in a cohort of 1027 consecutive patients (mean age, 50.5 years; 675 male and 352 female) with HBV-compensated cirrhosis who underwent liver CT (2007-2010). Associations of LSVR with hepatic decompensation and transplantation-free survival were evaluated using multivariable Cox proportional hazards and competing risk analyses, accounting for either the Child-Pugh score (CPS) or Model for End Stage Liver Disease (MELD) score and other variables. The risk of the liver-related events was estimated using Kaplan-Meier analysis and the Aalen-Johansen estimator. Results: After adjustment for either CPS or MELD and other variables, LSVR was identified as a significant independent predictor of hepatic decompensation (hazard ratio for LSVR increase by 1, 0.71 and 0.68 for CPS and MELD models, respectively; p < 0.001) and transplantation-free survival (hazard ratio for LSVR increase by 1, 0.8 and 0.77, respectively; p < 0.001). Patients with an LSVR of < 2.9 (n = 381) had significantly higher 3-year risks of hepatic decompensation (16.7% vs. 2.5%, p < 0.001) and liver-related death or transplantation (10.0% vs. 1.1%, p < 0.001) than those with an LSVR ≥ 2.9 (n = 646). When patients were stratified according to CPS (Child-Pugh A vs. B-C) and MELD (< 10 vs. ≥ 10), an LSVR of < 2.9 was still associated with a higher risk of liver-related events than an LSVR of ≥ 2.9 for all Child-Pugh (p ≤ 0.045) and MELD (p ≤ 0.009) stratifications. Conclusion: The LSVR measured on CT can predict hepatic decompensation and transplantation-free survival in patients with HBV-compensated cirrhosis.