• 천문학회보
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• 제36권1호
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• pp.62.2-62.2
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• 2011

It is well known that the cluster environment can change the atomic gas properties of galaxies through tidal interactions and/or by the hot cluster medium. Meanwhile, the molecular gas is expected to be less vulnerable to its surroundings due to its higher density, and no obvious influence of the environment on the molecular gas properties had been found among cluster spirals until recently. However, in a recent study by Fumagalli et al. (2009) of a sub-sample of Virgo spirals, it has been suggested that HI deficient galaxies can be also CO deficient. In order to further investigate if the HI deficiency indeed can result in the deficiency in molecular gas content, we compare the global CO and HI gas properties of Virgo spirals with those of galaxies in the Ursa Major cluster and the Pisces cluster, much lower density environments than Virgo. We discuss possible consequences of molecular gas deficiency in star formation activity of spiral galaxies in high density environment.

• Journal of Multimedia Information System
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• 제4권4호
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• pp.189-194
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• 2017

In this study, we propose a method which is based on "Image segmentation by histogram thresholding using hierarchical cluster analysis"/HCA/ and "A nonparametric approach for histogram segmentation"/NHS/. HCA method uses that all histogram bins are one cluster then it reduces cluster numbers by using distance metric. Because this method has too many clusters, it is more computation. In order to eliminate disadvantages of "HCA" method, we used "NHS" method. NHS method finds all local minima of histogram. To reduce cluster number, we use NHS method which is fast. In our approach, we combine those two methods to eliminate disadvantages of Arifin method. The proposed method is not only less computational than "HCA" method because combined method has few clusters but also it uses local minima of histogram which is computed by "NHS".

• International Journal of Internet, Broadcasting and Communication
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• 제7권1호
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• pp.30-35
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• 2015

The most important factor within the wireless sensor network is to have effective network usage and increase the lifetime of the individual nodes in order to operate the wireless network more efficiently. Therefore, many routing protocols have been developed. The LEACH protocol presented by Wendi Hein Zelman, especially well known as a simple and efficient clustering based routing protocol. However, because LEACH protocol in an irregular network is the total data throughput efficiency dropped, the stability of the cluster is declined. Therefore, to increase the stability of the cluster head, in this paper, it proposes a stochastic cluster head selection method for improving the LEACH protocol. To this end, it proposes a SH-LEACH (Stochastic Cluster Head Selection Method-LEACH) that it is combined to the HEED and LEACH protocol and the proposed algorithm is verified through the simulation.

• International Journal of Internet, Broadcasting and Communication
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• 제9권4호
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• pp.51-58
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• 2017

This paper deals with the improvement of cluster head selection method in L-SEP for heterogeneous nodes among hierarchical routing protocols of wireless sensor network. Wireless sensor networks are classified into homogeneous and heterogeneous network. In heterogeneous network, SEP, L-SEP are mainly used because cluster head selection probability is different depending on node type. But, since protocol based on SEP has different cluster head selection probabilities depending on the node type, clusters that transmit data inefficiently can be formed. to improve this, it is necessary to select the cluster head that minimizes the transmission distance of member node and the cluster head. Therefore, we propose a protocol that improve the cluster head selection method.

• The Journal of Asian Finance, Economics and Business
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• 제6권4호
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• pp.227-233
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• 2019

The study examines how business conditions, demand conditions and the role of government can influence the development of batik clusters in Pekalongan. This research is expected to be able to provide recommendations for both employers and local governments in order to help in optimizing the development of batik clusters. The research applied a quantitative research by engaging multiple regression analysis as an effort to understand the effect of the relationship between independent and dependent variables. In addition, this research was conducted in three largest batik clusters in Pekalongan, Indonesia namely batik cluster of Pasindon, Kauman, and Jenggot. These results indicate that business conditions positively affect the batik clusters development. It implies that the greater both business conditions in a cluster will lead the better the development. Indeed, the demand conditions also have an impact on the cluster development. This finding remarked that demand conditions are variable that need to be considered to development of batik cluster. Lastly, Government's role is confirmed that positively related to the Development of Batik Clusters. It implies that the more active the government's role in a cluster will have a good impact on the development of the cluster in certain area.

• 정보처리학회논문지A
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• 제8A권3호
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• pp.261-268
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• 2001

With the rapid growth of the Internet, various web-based businesses are creating a new environment in an imaginary space. However, this expanding Internet and user increase cause an overflow of transmission and numerous subordinate problems. To solve these problems, a parallel cluster system is produced using different methods. This thesis recommends a multi0distribution cluster group. It constructs a MPP dynamic distribution sub-cluster group using numerous low-priced and low-speed systems. This constructed sub-cluster group is then connected with a singular virtual IP to finally serve the needs of clients (users). This multi-distribution cluster group consists of an upper structure based on LVS and a dynamic serve cluster group centered around an SC-server. It conducts the workloads required from users in a parallel process. In addition to the web service, this multi-distribution cluster group can efficiently be utilized for the calculations which require database controls and a great number of parallel calculations as well as additional controls with result from the congestion of service.

• Asian Journal of Innovation and Policy
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• 제7권1호
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• pp.103-130
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• 2018

It is generally understood that clusters are the promoters of innovation and therefore, the attention of researchers has been increasingly to discern the factors driving innovation among the firms in a cluster, especially in a high-tech cluster. In this study, we identify the variables capturing the nature of a firm that possibly impact the absorptive capacity of a firm and subsequently ascertain their impact on the degree of interactions between a firm, and other firms and associated institutions within and outside a cluster, respectively. Furthermore, we probe the influence of these interactions as a whole on firm-level innovation. The study was carried out in the context of Bengaluru, which houses the densely interconnected network of innovation-intensive high-tech manufacturing firms forming a high-tech manufacturing cluster. Data were drawn from 101 high-tech manufacturing firms belonging to electronics, machine tools, electrical and pharmaceutical industries. Based on the cluster analysis and subsequent graphical analysis on each of the three profiled clusters, it was found that size and origin of a firm have significant impact on the degree of firm's interactions. In turn, higher dynamism of firms in terms of degree of interactions led to higher innovation performance.

• Journal of Information Processing Systems
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• 제10권1호
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• pp.36-54
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• 2014

Resource sharing is a major advantage of distributed computing. However, a distributed computing system may have some physical or virtual resource that may be accessible by a single process at a time. The mutual exclusion issue is to ensure that no more than one process at a time is allowed to access some shared resource. The article proposes a token-based mutual exclusion algorithm for the clustered mobile ad hoc networks (MANETs). The mechanism that is adapted to handle token passing at the inter-cluster level is different from that at the intra-cluster level. It makes our algorithm message efficient and thus suitable for MANETs. In the interest of efficiency, we implemented a centralized token passing scheme at the intra-cluster level. The centralized schemes are inherently failure prone. Thus, we have presented an intra-cluster token passing scheme that is able to tolerate a failure. In order to enhance reliability, we applied a distributed token circulation scheme at the inter-cluster level. More importantly, the message complexity of the proposed algorithm is independent of N, which is the total number of nodes in the system. Also, under a heavy load, it turns out to be inversely proportional to n, which is the (average) number of nodes per each cluster. We substantiated our claim with the correctness proof, complexity analysis, and simulation results. In the end, we present a simple approach to make our protocol fault tolerant.

• Journal of Information Technology Applications and Management
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• 제26권1호
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• pp.53-64
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• 2019

The purpose of this study is to find out the fast delivery route that several drones return a truck again after departing from it for delivery locations at each cluster while the truck goes through the cluster composed of several delivery locations. The main issue is to reduce the total delivery time composed of the delivery time by relatively slow trucks via clusters and the sum of maximum delivery times by relatively fast drones in each cluster. To solve this problem, we use a three-step heuristic approach. First, we cluster the nearby delivery locations with minimal number of clusters satisfying a constraint of drone flight distance to set delivery paths for drones in each cluster. Second, we set an optimal delivery route for a truck through centers of the clusters using the TSP model. Finally, we find out the moved centers of clusters while maintaining the delivery paths for the truck and drones and satisfying the constraint of drone flight. distance in the two-dimensional region to reduce the total delivery time. In order to analyze the effect of this study model according to the change of the number of delivery locations, we developed a R-based simulation prototype and compared the relative efficiency, and performed paired t-test between TSP model and the cluster-based models. This study showed its excellence through this experimentation.

• 교육시설
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• 제6권2호
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• pp.13-23
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• 1999

This paper seeks to find out the policies of management and layout of middle school rooms for the community people's use. This paper surveys community's needs with respect to both the use of school rooms before, during, and after classes and preferences of use of school rooms. This paper adopts two experimental case studies to find out the models. It uses t-test analysis of the statistics to find out community people's preferences for the use of school rooms between two communities in an urban area, and uses simple and multiple regression analyses to develop models concerning community people's uses of school rooms before, during, and after classes. It also uses cluster analysis to find out the cluster among community people's preference of school rooms. It found, first, that community people's use of school rooms after class can be influenced by the uses of a play ground, a music classroom, an audio visual classroom, and a gymnasium. The use during regular classes is related to the uses of the fine arts classroom, a general classroom, a home economics classroom, a gymnasium, and a playground. The use before class is affected by the uses of a fine arts classroom, a playground, and a library. It also found that, with respect to community people's preferential use of school rooms, the rooms can be clustered as a cluster of laboratories such as a general classroom, a music room, a fine arts classroom, a science classroom, a home economics classroom, and a technique classroom, a cluster of athletic areas such as a gymnasium and a playground, and a cluster of supporting facilities such as a library, an audio visual classroom, and a computer classroom. Those clusters can also be clustered in more detail, i. e., that both a general classroom and playground can be apart from a cluster of laboratories or a cluster of supporting facilities; that an audio visual classroom can be fostered into a cluster with a home economics affairs classroom and a technique classroom. Finally this paper suggests policies of management and layout of school rooms.