• Journal of Digital Convergence
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• v.18 no.3
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• pp.1-12
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• 2020

The purpose of this study is to explore the trend of blockchain technology through analysis of patents and news articles using text mining, and to suggest the blockchain policy agenda by grasping social interests. For this purpose, 327 blockchain-related patent abstracts in Korea and 5,941 full-text online news articles were collected and preprocessed. 12 patent topics and 19 news topics were extracted with latent dirichlet allocation topic modeling. Analysis of patents showed that topics related to authentication and transaction accounted were largely predominant. Analysis of news articles showed that social interests are mainly concerned with cryptocurrency. Policy agendas were then derived for blockchain development. This study demonstrates the efficient and objective use of an automated technique for the analysis of large text documents. Additionally, specific policy agendas are proposed in this study which can inform future policy-making processes.

• The KIPS Transactions:PartC
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• v.10C no.4
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• pp.387-396
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• 2003

Many studies have been done on secure kernel and encryption filesystem for system security. Secure kernel can protect user or system data from unauthorized and/or illegal accesses by applying various access control policy like ACL, MAC, RBAC and so on, but cannot protect user or system data from stealing backup media or disk itself. In addition to access control policy, there are many studies on encryption filesystem that encrypt file data within system level. However few studies have been done on combining access control policy and encryption filesystem. In this paper we proposed a new encryption filesystem that provides a transparency to the user by integrating encryption service into virtual filesystem layer within secure kernel that has various access control policies. Proposed encryption filesystem can provide a simple encryption key management architecture by using encryption keys based on classes of MAC policy and overcome a limit of physical data security of access control policy for stealing.

• The KIPS Transactions:PartD
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• v.12D no.4 s.100
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• pp.507-520
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• 2005

The R-trees are usually used for an index of trajectories in moving-objects databases. However, they need to access a number of nodes to trace same trajectories because of considering only a spatial proximity. Overlaps and dead spaces should be minimized to enhance the performance of range queries in moving-objects indexes. Trajectories of moving-objects should be preserved to enhance the performance of the trajectory queries. In this paper, we propose the TP3DR-tree(Trajectory Preserved 3DR-tree) using clusters of trajectories for range and trajectory queries. The TP3DR-tree uses two split policies: one is a spatial splitting that splits the same trajectory by clustering and the other is a time splitting that increases space utilization. In addition, we use connecting information in non-leaf nodes to enhance the performance of combined-queries. Our experiments show that the new index outperforms the others in processing queries on various datasets.

• KIPS Transactions on Computer and Communication Systems
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• v.8 no.5
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• pp.111-118
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• 2019

Recent graphic processing units (GPUs) provide high throughput by using powerful hardware resources. However, massive memory accesses cause GPU performance degradation due to cache inefficiency. Therefore, the performance of GPU can be improved by reducing thread parallelism when cache suffers memory contention. In this paper, we propose a dynamic warp scheduler which controls thread parallelism according to degree of cache contention. Usually, the greedy then oldest (GTO) policy for issuing warp shows lower parallelism than loose round robin (LRR) policy. Therefore, the proposed warp scheduler employs the LRR warp scheduling policy when Miss Status Holding Register(MSHR) utilization is low. On the other hand, the GTO policy is employed in order to reduce thread parallelism when MSHRs utilization is high. Our proposed technique shows better performance compared with LRR and GTO policy since it selects efficient scheduling policy dynamically. According to our experimental results, our proposed technique provides IPC improvement by 12.8% and 3.5% over LRR and GTO on average, respectively.

• Science & Technology Policy
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• v.7 no.5 s.98
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• pp.8-11
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• 1997

• Journal of Labour Economics
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• v.21 no.1
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• pp.195-227
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• 1998

• Daejeon Development Forum
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• s.38
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• pp.173-183
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• 2011

• Proceedings of the KHMA Conference
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• 2010.05a
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• pp.340-340
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• 2010

• Journal of Korea Fair Competition Federation
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• no.162
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• pp.28-37
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• 2012

• Journal of Korea Fair Competition Federation
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• no.162
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• pp.38-45
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• 2012