• KIPS Transactions on Computer and Communication Systems
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• v.2 no.5
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• pp.209-216
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• 2013

In traditional social network analysis, the betweenness centrality measure has been heavily used to identify the relative importance of nodes in terms of message delivery. Since the time complexity to calculate the betweenness centrality is very high, however, it is difficult to get it of each node in large-scale social network where there are so many nodes and edges. In this paper, we define a new type of network, called the expanded ego network, which is built only with each node's local information, i.e., neighbor information of the node's neighbor nodes, and also define a new measure, called the expended ego betweenness centrality. Through the intensive experiment with Barab$\acute{a}$si-Albert network model to generate the scale-free networks which most social networks have as their embedded feature, we also show that the nodes' importance rank based on the expanded ego betweenness centrality has high similarity with that based on the traditional betweenness centrality.

• Anxiety and mood
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• v.9 no.1
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• pp.10-18
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• 2013

The increasing suicide rate is a serious problem in Korea. Because of increased awareness of suicidality as a problem and because completed suicide is the fourth leading cause of death, it is very important to assess the risk of suicide. The purpose of this review is to provide a systematic examination of predictive validity of measures of suicidal ideation and behavior. A number of instruments are described as useful for identifying individuals "at high risk" for suicidal behavior. However, the predictive validity for most suicide measures has not been established. The present review only includes suicide assessment instruments with published predictive validity. In addition to evaluating the suicide assessment with respect to predictive validity, the present review describes and summarizes the psychometric properties of each measure. In conclusion, because of the complexity of studying the risk of suicide and the paucity of well-designed studies, it is extremely difficult to compare and generalize these findings. In addition, only a few instruments, such as the Scale for Suicide Ideation, Suicide Intent Scale and the Beck Hopelessness Scale, have been found to be significant risk factors for completed suicide. Another problem in the field involves that there have been few suicide measures designed for elderly populations. Clearly, future research is needed to investigate the predictive validity of standardized measures for completed suicide, especially targeting elderly populations.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.38 no.4
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• pp.335-343
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• 2001

The conventional wavelet-based fractal image coding has the disadvantage that the encoding takes a long time, since each range block finds the best domain in the image. In this Paper, we propose wavelet-based fractal image coding using SAS(Self Affine System) method and multi-scale factor. It consists of the range and domain blocks in DWT(discrete wavelet transform) region. Using SAS method, the proposed method is that the searching process of the domain block is not required, and the range block selects the domain which is relatively located the same position in the upper level. The proposed method can perform a fast encoding by reducing the computational complexity in the encoding process. In order to improve the disadvantage of SAS method which is reduced image qualify, the proposed method is improved image qualify using the different scale factors for each level. As a result, there is not influence on an image quality, the proposed method is enhanced the encoding time and compression ratio, and it is able to the progressive transmission.

• Journal of the Korean Institute of Gas
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• v.4 no.4 s.12
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• pp.42-49
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• 2000

Due to their size and complexity, it is very difficult to make diagnostic system for the whole chemical processes. Therefore, a systematic approach is required to decompose larpge-scale process into sub-processes and then diagnose them. This paper suggests a method for the minimization of knowledge base and flexible diagnosis to be used in qualitative fault diagnosis based on Fault-Effect Tree model. The system can be decomposed for flexible diagnosis, size reduction of knowledge base, and consistent construction of complex knowledge base. The new node, gate-variable, is introduced to connect the cause-effect relationships of each sub-process. For on-line diagnosis, off-line analysis is performed to construct Fault-Effect Trees of gate-variables as well as activation conditions of gate-variables. On-line diagnosis strategy is modified to get the same diagnosis result without system decomposition. The proposed method is illustrated with a fault diagnosis system for a large-scale boiler plant.

• Journal of Korean Academy of Nursing
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• v.15 no.2
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• pp.49-61
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• 1985

It is assumed that the more society advances in its complexity and development, the more people pay attention to their health and accordingly the more people tend to practice health protective behavior. Most of human behavior is based on social inter-actions. The concept in Locus of Control has been developed from social learning theory to help better understanding the social phenomena affecting human behavior. Multidimensional Health Locus of Control is consisted of three dimensions: Internal, Powerful Others and Chance. This study was conducted to find out the health protective behavior patterns of the people and its relationship with Health Locus of Control as an influencing factor to their behavior. All the subjects in this study were the ones of the bank employees in Seoul, Among the total of 1,430 bank employees, 761 were chosen as a sampled subjects. Questionnair survey was conducted from March 4 to March 13, 1985. Research instruments used in this study were two kinds, one was the Health Locus of Control Scale developed by Wallston & Wallston and the other was the Measuring Scale for Health Protective Behavior developed by the investigator. Analysis of data was done by using Descriptive Statistics, X²-test, t-test, ANOVA, Pearson's correlation coefficient. The results of this study are summarized as follows: The mean score of Internal was 24.1, Powerful others was 19.7 and Chance was 15.3 out of maximum range of 6-30 respectively. The mean score of Health Protective Behavior Scale fell as 53.2 out of a maximum range of 18-90. Internals were more likely closely related with sex, educational levels and religion, Powerful others were related with age, educational levels and the number of family members. Chances were related with edu cational levels. The older the subjects were, the more concerned about their health. They tended to practice more favorable health protective behaviors. Furthermore, married people tended to fay more attention to their health than single individuals. Also, the number of family members and religion affected their attitudes in the health protective behavior patterns. Internals and Powerful Others were related with health protective behaviors. If one believes he can do something about his health and others play a significant role on his health, he is more apt protective patterns more suitable for health and actually shows that he is better off.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.40 no.3
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• pp.92-98
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• 2017

The rapid growth of engineering technology and the emergence of systemized and large-scale engineering systems have resulted in complexity and uncertainty throughout the lifecycle activities of engineering systems. This complex and large-scale engineering system consists of numerous components, but system failure can be caused by failure of any one of a number of components. There is a real difficulty in managing such a complex and large-scale system as a part. In order to efficiently manage the system and have high reliability, it is necessary to structure a system with a complex structure as a sub-system. Also, in the case of a system in which cause of failures exist at the same time, it is required to identify the correlation of the components lifetime and utilize it for the design policy or maintenance activities of the system. Competitive risk theory has been used as a theory based on this concept. In this study, we apply the competitive risk theory to the models with combined structure of series and parallel which is the basic structure of most complex engineering systems. We construct a competing risks model and propose a mathematical model of net lifetime and crude lifetime for each cause of failure, assuming that the components consisting a parallel system are mutually dependent. In addition, based on the constructed model, the correlation of cause of failure is mathematically analyzed and the hazard function is derived by dividing into net lifetime and crude lifetime.

• International Journal of Contents
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• v.16 no.4
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• pp.16-25
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• 2020

The size of observation data in astronomy has been increasing exponentially with the advents of wide-field optical telescopes. This means the needs of changes to the way used for large-scale astronomy data analysis. The complexity of analysis tools and the lack of extensibility of computing environments, however, lead to the difficulty and inefficiency of dealing with the huge observation data. To address this problem, this paper proposes a workflow execution system for analyzing large-scale astronomy data efficiently. The proposed system is composed of two parts: 1) a workflow execution manager and its RESTful endpoints that can automate and control data analysis tasks based on workflow templates and 2) an elastic resource manager as an underlying mechanism that can dynamically add/remove virtualized computing resources (i.e., virtual machines) according to the analysis requests. To realize our workflow execution system, we implement it on a testbed using OpenStack IaaS (Infrastructure as a Service) toolkit and HTCondor workload manager. We also exhaustively perform a broad range of experiments with different resource allocation patterns, system loads, etc. to show the effectiveness of the proposed system. The results show that the resource allocation mechanism works properly according to the number of queued and running tasks, resulting in improving resource utilization, and the workflow execution manager can handle more than 1,000 concurrent requests within a second with reasonable average response times. We finally describe a case study of data reduction system as an example application of our workflow execution system.

• IEIE Transactions on Smart Processing and Computing
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• v.1 no.3
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• pp.133-142
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• 2012

This paper presents a salient region detection algorithm for auto-focusing based on the characteristics of a human's visual attention. To describe the saliency at the local, regional, and global levels, this paper proposes a set of novel features including multi-scale local contrast, variance, center-surround entropy, and closeness to the center. Those features are then prioritized to produce a saliency map. The major advantage of the proposed approach is twofold; i) robustness to changes in focus and ii) low computational complexity. The experimental results showed that the proposed method outperforms the existing low-level feature-based methods in the sense of both robustness and accuracy for auto-focusing.

• Proceedings of the KSME Conference
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• 2007.05b
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• pp.2079-2084
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• 2007

A small-scale thermoelectric cooling system was built in an effort to enhance the performance of the refrigeration system by utilizing the water-cooled jacket which was attached on the hot side of the thermoelectric module. Considered design parameters for the water-cooled jacket included the geometry of the flow passage inside the jacket and the flow rate of cooling water. The higher flow rate of cooling water in the jacket resulted in a better performance of the refrigeration system. The introduction of geometrical complexity of the cooling water flow passage to the cooling jacket also showed significant improvement on the performance of the thermoelectric refrigeration system such as the cooling capacity and the COP of the refrigeration system.

• Journal of Navigation and Port Research
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• v.27 no.3
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• pp.329-333
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• 2003

Study of the background and state of Osaka's waterfront space development and analysis of the functions of 22 chosen major facilities of development project reveals the following four types: amenity-oriented development, large-scale synthesis type development, renewal compound area type development, exchange communication promotion type development. Osaka bay area has served primely as the base of harbors, industry and energy, while analysis of the ongoing project has found that the city has been making a functional transition to a type of development to live up to the needs of the times, suggesting that is wise that Korea's future direction of waterfront development be oriented toward environmental-friendly development by taking advantage of low-density area's natural resources. Given the plurality and complexity of the law of coastal zone, what is needed is a legal maintenance for coastal zone's clear-cut coordinating function and for environmental-friendly development with the limitations of seaside and coastal functions in mind.