• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.30 no.5D
• /
• pp.453-459
• /
• 2010

In the study of traffic safety, it is utmost important to obtain more reliable estimates of the expected crashes for a site (or a segment). The observed crashes have been mainly used as the estimate of the expected crashes in Korea, while the empirical Bayes (EB) estimates based on the Poisson-gamma mixture model have been used in the USA and several European countries. Although numerous studies have used the EB method for estimating the expected crashes and/or the effectiveness of the safety countermeasures, no past studies examine the difference in the estimation errors between the two estimates. Thus, this study compares the estimation errors of the two estimates using a Monte Carlo simulation study. By analyzing the crash dataset at 3,000,000 simulated sites, this study reveals that the estimation errors of the EB estimates are always less than those of the observed crashes. Hence, it is imperative to incorporate the EB method into the traffic safety research guideline in Korea. However, the results show that the differences in the estimation errors between the two estimates decrease as the uncertainty of the prior distribution increases. Consequently, it is recommended that the EB method be used with reliable hyper-parameter estimates after conducting a comprehensive examination on the estimated negative binomial model.

• Journal of the Korean Institute of Intelligent Systems
• /
• v.6 no.2
• /
• pp.52-56
• /
• 1996

In trainir~ga back-propagation neural network, the learning speed of the network is greatly affected by its learning rate. Most of off-line fashioned learning-rate selection methods, however, are empirical except for some deterministic methods. It is very tedious and difficult to find a good learning rate using the empirical methods. The deterministic methods cannot guarantee the quality of the quality of the learning rate. This paper proposes a new learning-rate selection method. Our off-line fashioned method selects a good learning rate through stochastically searching process using evolutionary programming. The simulation results show that the learning speed achieved by our method is superior to that of deterministic and empirical methods.

• Korean Journal of Culture and Social Issue
• /
• v.13 no.1
• /
• pp.63-89
• /
• 2007

This study introduces major models of psychological debriefing that has been utilized as an early psychological intervention after traumatic incidents and examines the controversy on the effects of psychological debriefing. It is difficult to make consistent conclusions regarding its effects based on the previous research data. Therefore, this study examines the major issues related to psychological debriefing and suggests the important points for best practice in crisis situations.

• Proceedings of the Korean Society for Cognitive Science Conference
• /
• 2000.05a
• /
• pp.235-240
• /
• 2000

창의성 연구는 개인적, 사회적 맥락에서 고려해야 할 다양한 시사점을 가진 분야이다. 하지만 지금까지 창의성 연구는 창의성 자체에 대한 개념이 명확하지 않을 뿐 아니라, 창의성을 태어날 때부터 타고나는 고유한 영역이라는 인식 때문에 그에 대한 연구가 비교적 부족한 실정이다. 본 연구에서는 창의성이 새로운 정보를 기존 지식과 결합하여 이를 문제상황에서 적용하여 유용함을 입증하는 행위라는 전제하에, 각 개인에게 내재된 창의적 사고 능력이 특정한 지시 혹은 학습방법(소리내어 가르치기)의 경험을 통해 발현될 수 있으리라 보았다. 창의성의 핵심요소인 통합적, 분석적, 실용적 사고능력을 측정하여 창의성이 높고, 낮은 집단을 구분하고, 이를 근거로 게임 규칙을 소리내어 가르치기 경험을 한 집단과 통제집단(단순암기)으로 각각 구분하여 게임에서 승리, 즉 창의적 문제해결이 소리내어 가르치기 방법을 통해 실현될 수 있음을 알아보고자 했다. 창의적 사고능력은 소리내어 가르치기를 경험한 집단에서 유의미하게 발현되었다. 또한 소리내어 가르치는 경험을 한 실험참가자들은 프로토콜 분석에서 보다 정교화된 게임의 규칙을 생성하였으며, 게임의 규칙을 정확히 알고 있는 것으로 나타났다. 이는 가르치는 경험을 통해 새로운 정보를 보다 잘 조직화하고, 이를 실제 문제상황에 적용한 것으로 해석되었다.

• Journal of Korean Society of Industrial and Systems Engineering
• /
• v.31 no.2
• /
• pp.132-140
• /
• 2008

본 논문은 시간 제약을 갖는 차량 라우팅 문제를 해결하기 위해 유전자 알고리듬과 부분 최적화 알고리듬을 적용한 방법을 소개한다. 유전자 알고리듬에서의 염색체는 노드를 나타내는 정수의 순열로 표현되어 직접적인 해를 나타내지 않지만, 경험적 방법에 의한 해석을 통해 유효한 해로 변형되도록 하였다. 유전자 알고리듬에 의해 생성된 주어진 수의 우수한 해들에는 세 부분 최적화 방법이 순차적으로 적용되어 보다 좋은 해를 생성하도록 하였다. 부분 최적화 방법들에 의한 해는 다시 유전자 알고리듬의 해로 바뀌지 않도록 하여 두 알고리듬은 느슨하게 연결되도록 하였다. 솔로몬의 데이터를 이용한 실험에서 본 연구에서의 방법이 모든 문제에 대해 우수한 해를 생성함을 나타내었다. 특히, 지금까지 알려진 가장 우수한 경험적 방법에 비교될 만한 결과를 가져옴을 보였다.

• Journal of the Korean Data and Information Science Society
• /
• v.28 no.1
• /
• pp.87-98
• /
• 2017

The multivaiate empirical distribution function (MEDF) is defined in this work. The MEDF's expectation and variance are derived and we have shown the MEDF converges to its real distribution function. Based on random samples from bivariate standard normal distribution with various correlation coefficients, we also obtain MEDFs and propose two kinds of graphical methods to visualize MEDFs on two dimensional plane. One is represented with at most n stairs with similar arguments as the step function, and the other is described with at most n curves which look like bivariate quantile vector. Even though these two descriptive methods could be expressed with three dimensional space, two dimensional representation is obtained with ease and it is enough to explain characteristics of bivariate distribution functions. Hence, it is possible to visualize trivariate empirical distribution functions with three dimensional quantile vectors. With bivariate and four variate illustrative examples, the proposed MEDFs descriptive plots are obtained and explored.

• The Journal of the Korea Contents Association
• /
• v.19 no.9
• /
• pp.658-665
• /
• 2019

In the era of the rapid development of a tremendous number of new technologies and products, the emotional communication between products and users has become an important research topic. However, the user's emotional measurement methods have not been widely used in the field of product design. Besides, as an important space that can improve people's life quality and urban entertainment at the emotional level, seaside space also creates an atmosphere of frequent emotional communication among tourists, landscape and environmental facilities. To deduce the applicability and advantages and disadvantages of the experiential emotional measurement method in product design, this paper took the seaside seat users of Haeundae as the object and carried out the Self-report of the experiential emotional measurement method. Specifically, the experiment of Self-report was divided into two stages: prior survey and subsequent main investigation. Then the hypothesis was verified by using Bivariate Regression and Multiple Regression through SPSS. Furthermore, through the experiment of the Self-report, the applicability and advantages and disadvantages of experiential emotional measurement method in product design were derived. In the future, based on the applicability, advantages and disadvantages of the experiential emotional measurement method derived in this study, it is expected to become the fundamental and reliable data for the development of emotional measurement methods that can be suitable for product design.

• Journal of Korea Port Economic Association
• /
• v.40 no.1
• /
• pp.151-163
• /
• 2024

This study sought to confirm the impact of analytical methods and behavioral economic theory factors on decision-making when making chartering decisions in the dry bulk shipping market. This study on chartering decision-making model was began to verify why shipping companies do not make rational decision-making and behavior based on analytical methods such as freight prediction and process of alternative selection in the same market situation. To understand the chartering decision-making model, it is necessary to study the impact of behavioral economic theory such as heuristics, loss aversion, and herding behavior on chartering decision-making. Through AHP analysis, the importance of the method factors relied upon in chartering decision-making. The dependence of the top factors in chartering decision-making was in the following order: market factors, heuristics, internal factors, herding behavior, and loss aversion. Market factors, heuristics, and internal factors. As for detailed factors, spot freight index and empirical intuition were confirmed as the most important factors relied on when making decisions. It was confirmed that empirical intuition is more important than internal analysis, which is an analytical method. This study can be said to be meaningful in that it academically researched and proved the bounded rationality of humans, which cannot be fully rational, and sometimes relies on experience or psychological tendencies, by applying it to the chartering decision-making model in the dry bulk shipping market. It also suggests that in the dry bulk shipping market, which is uncertain and has a high risk of loss due to decision-making, the experience and insight of decision makers have a very important impact on the performance and business profits of the operation part of shipping companies. Even though chartering are a decision-making field that requires judgment and intuition based on heuristics, decision-makers need to be aware of this decision-making model in order to reduce repeated mistakes of deciding contrary to market situation. It also suggests that there is a need to internally research analytical methods and procedures that can complement heuristics such as empirical intuition.

• Journal of Korean Society of Transportation
• /
• v.31 no.6
• /
• pp.67-89
• /
• 2013

This study is to perform empirical analysis on observational before-after studies in Naive Method, Comparison Group(CG) Method and Empirical Bayes(EB) Method, and to compare with their results and to propose ways to apply to evaluation researches. For this purpose, the evaluation of road safety audit executed on Y$\breve{o}$ng-dong freeway in 2005 and 2006 was performed. As a result, all three methods have showed improved effects due to safety treatments. The safety effectiveness of Naive method is the largest, CG Method is the second and EB method is the last. The results of Naive method are overestimated due to the trend of reducing traffic accidents and those of CG method are affected by the external casual effects of comparison group. In the EB method, as "regression to the mean" phenomenon are controlled by reference group's accident model, it's result is relatively more accurate than that of other methods. In the conduct of evaluation studies, the analysts have to understand the pros and cons of each evaluation method. And after leading the survey on accident trends of related all sites, evaluation analysis is performed to be able to minimize bias.

• Journal of the Korean Society of Floral Art and Design
• /
• no.43
• /
• pp.39-56
• /
• 2020

This study is on the creation of floral art works based on the intuitive insight acquired by methodological process of ruminating the experienced meaningful events of the artists utilizing sensible perception. The researcher used the narration and visualization techniques. The narration process adopted the writing technique of subjective impression, emotion, stream of consciousness to capture sensations of subconscious state, which were applied in three steps of 'the exploration of experiences', 'the concretion of experiences', and 'the creation of meaning out of experiences'. The visualization process adopted collection, selection, classification, and interpretation of related images, which were applied in three methods of 'the creation of images', 'the utilization of intuition', and 'the perception through remembering'. Finally 5 art works of 'Hammock is Good', 'At the Rooftop with Warm Sunshine', 'Standing at the Waterside Alone', 'Dizziness at Hot Sand Field', and 'Having Good Time at a Botanical Garden'were created through the combination of these two methods mentioned above and complementary research and writing. The meaningfulness of this research lies in presenting methodological approaches of utilizing narration and visualization of experiences in art creation process.