• Journal of KIISE:Databases
• /
• v.30 no.6
• /
• pp.651-665
• /
• 2003

To reduce cache misses emerges as the most important issue in today's situation of main memory databases, in which CPU speeds have been increasing at 60% per year, and memory speeds at 10% per year. Recent researches have demonstrated that cache-conscious index structure such as the CR-tree outperforms the R-tree variants. Its search performance can be poor than the original R-tree, however, since it uses a lossy compression scheme. In this paper, we propose alternatively a cache-conscious version of the R-tree, which we call MR-tree. The MR-tree propagates node splits upward only if one of the internal nodes on the insertion path has empty room. Thus, the internal nodes of the MR-tree are almost 100% full. In case there is no empty room on the insertion path, a newly-created leaf simply becomes a child of the split leaf. The height of the MR-tree increases according to the sequence of inserting objects. Thus, the HeightBalance algorithm is executed when unbalanced heights of child nodes are detected. Additionally, we also propose the CCMR-tree in order to build a more cache-conscious MR-tree. Our experimental and analytical study shows that the two-dimensional MR-tree performs search up to 2.4times faster than the ordinary R-tree while maintaining slightly better update performance and using similar memory space.

• Journal of the Korean Institute of Traditional Landscape Architecture
• /
• v.36 no.1
• /
• pp.34-44
• /
• 2018

In the Ancient Mesopotamia, Egypt, Judas, Greece, and Rome, Phoenix dactylifera was planted in gardens or orchards to signify life, blessing, and victory. Branches of Phoenix dactylifera, likened to high and precious, were referred to one of the gifts to the king in the second century BC and have been used in the Feast of Tabernacles. And they were engraved on the walls of the temple and along with cherub. Besides, Phoenix dactylifera is compared with a righteous person in the Bible since it grows straight despite strong winds. And, it was used as a symbol of honesty, justice, and right. Churches call the week before Easter Palm Sunday since the crowd laid the leaves of date palm trees on the road and shouted "Hosanna" while waving the date palm branches when Jesus entered Jerusalem. Moreover, pilgrim in the Middle Ages was called 'Palmer' in English due to custom of returning with the leaves and branches of date palm trees as a memorial of the Holy Land pilgrimage. This study analyzes naming issue of Phoenix dactylifera through the old literature and 27 versions of the most influential Bibles in History of Bible Translation in Korea, China, and Japan. Phoenix dactylifera is translated into Chinese as '棕櫚(Trachycarpus fortunei)', a native tree of China. 棕櫚 is similar to Phoenix dactylifera, but its fruit and leaf are quite distinct. This being so, translating Phoenix dactylifera as 棕櫚 has a limit to convey symbolic meaning adequately. In the Japanese Bible, on the other hand, Phoenix dactylifera is translated as 'なつめやし(Natsumeyashi)' meant date palm tree. Most of Protestant Bible in Korea use 'Jongryeo' like Chinese Bible while translation in Korean Catholic Bible(2005) varies from one scripture to another: 'Yaja Namu (Palm Tree)' - 38 times, 'Jongryeo Namu' - 5 times, and 'Daechu Yaja Namu (Date Palm Tree)' - 3 times. Date Palm Tree, 'Jongryeo Tree', and Palm Tree don't grow in Korea. However, they had long been recognized as Haejo(海棗), Jongryeo(?櫚), and Yaja(椰子) respectively through China and Japan. Each of them called by a distinct name correspond with its own characteristic and used separately in Korean Classics as Jongryeo and Haejo were identified in ancient Chinese literatures. It seems that more confusion was raised since 'Palm' was translated as 'Jongryeo' in several books including "?藤和英大辭典 (1915)", "Modern 朝鮮外來語辭典(1938)", and "Latin-Korean Dictionary(1995)". However, the Latin term 'Palmae' is translated into English as either palm tree or date palm. The results of this study suggest that more accurate translation of Phoenix dactylifera in the Bible would be 'Daechu Yaja Namu (Date Palm Tree)' and using different name fit for its own characteristic would be more appropriate.

• Proceedings of the Korean Institute of Intelligent Systems Conference
• /
• 2003.09a
• /
• pp.195-204
• /
• 2003

Network optimization is being increasingly important and fundamental issue in the fields such as engineering, computer science, operations research, transportation, telecommunication, decision support systems, manufacturing, and airline scheduling. Networks provide a useful way to modeling real world problems and are extensively used in practice. Many real world applications impose on more complex issues, such as, complex structure, complex constraints, and multiple objects to be handled simultaneously and make the problem intractable to the traditional approaches. Recent advances in evolutionary computation have made it possible to solve such practical network optimization problems. The invited talk introduces a thorough treatment of evolutionary approaches, i.e., hybrid genetic algorithms approach to network optimization problems, such as, fixed charge transportation problem, minimum cost and maximum flow problem, minimum spanning tree problem, multiple project scheduling problems, scheduling problem in FMS.

• Proceedings of the Korea Information Processing Society Conference
• /
• 2000.10a
• /
• pp.837-840
• /
• 2000

For secure communications in using multicast applications such as Cable-TV, It is essential for us to manage shared keys to encrypt/decrypt data through crypto algorithm as DES, which is called Group Key Management. In GKM, It is a hot issue that reduces the number of join/leave operation and subgroup key in key tree model. In this paper, we propose optimized mechanism of group key management required for providing multicast security.

• Proceedings of the Korean Information Science Society Conference
• /
• 2004.04a
• /
• pp.430-432
• /
• 2004

Multicasting is an efficient means of one to many (or many to many) communications. Due to the frequent and unpredictable topology changes, multicast still remains as challenge and no one-size-fits-all protocol could serve all kinds of needs in ad hoc network. Protocols and approaches currently proposed on this issue could be classified mainly into four categories, tree-based, meshed-based, statelessness and hybrid. In this article, we borrow the concept of Eulerian ring in graph theory and propose a novel ring-based multicast framework--Hierarchical Eulerian Ring-Oriented Multicast Architecture (HEROMA) over wireless mobile Ad hoc network. It is familiar with hybrid protocol based on mesh and tree who concentrates on efficiency and robustness simultaneously. Architecture and recovery algorithm of HEROMA are investigated in details. Simulation result is also presented, which show different level of improvements on end-to-end delay in scenario of small scale.

• Journal of the Korean Institute of Telematics and Electronics B
• /
• v.30B no.4
• /
• pp.27-36
• /
• 1993

This paper proposes a shortest path allocation algorithm over the processors on the hypercube system based on the message passing techniques with the optimized module allocation. On multiprocessor systems, how to divide one task into multiple tasks efficiently is an important issue due to the hardness of the life cycle estimation of each process. To solve the life cycle discrepancies, the appropriate task assignment to each processor and the flexible communications among the processors are indispensible. With the concurrent program execution on hypercube systems, each process communicaties to others with the method of message passing. And, each processor has its own memory. The proposed algorithm generates a callable tree out of the module, assigns the weight factors, constructs the allocation graph, finds the shortest path allocation tree, and maps them with hypercube.

• Journal of Information Processing Systems
• /
• v.18 no.6
• /
• pp.822-829
• /
• 2022

According to existing study into the remote fault diagnosis procedure, the current diagnostic approach has an imperfect decision model, which only supports communication in a close distance. An Internet of Things (IoT)-based remote fault diagnostic approach for wind power equipment is created to address this issue and expand the communication distance of fault diagnosis. Specifically, a decision model for active power coordination is built with the mechanical energy storage of power generation equipment with a remote diagnosis mode set by decision tree algorithms. These models help calculate the failure frequency of bearings in power generation equipment, summarize the characteristics of failure types and detect the operation status of wind power equipment through IoT. In addition, they can also generate the point inspection data and evaluate the equipment status. The findings demonstrate that the average communication distances of the designed remote diagnosis method and the other two remote diagnosis methods are 587.46 m, 435.61 m, and 454.32 m, respectively, indicating its application value.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
• /
• v.17 no.1
• /
• pp.229-249
• /
• 2022

This paper investigates machine learning models for predicting the designation of administrative issues in the KOSDAQ market through various techniques. When a company in the Korean stock market is designated as administrative issue, the market recognizes the event itself as negative information, causing losses to the company and investors. The purpose of this study is to evaluate alternative methods for developing a artificial intelligence service to examine a possibility to the designation of administrative issues early through the financial ratio of companies and to help investors manage portfolio risks. In this study, the independent variables used 21 financial ratios representing profitability, stability, activity, and growth. From 2011 to 2020, when K-IFRS was applied, financial data of companies in administrative issues and non-administrative issues stocks are sampled. Logistic regression analysis, decision tree, support vector machine, random forest, and LightGBM are used to predict the designation of administrative issues. According to the results of analysis, LightGBM with 82.73% classification accuracy is the best prediction model, and the prediction model with the lowest classification accuracy is a decision tree with 71.94% accuracy. As a result of checking the top three variables of the importance of variables in the decision tree-based learning model, the financial variables common in each model are ROE(Net profit) and Capital stock turnover ratio, which are relatively important variables in designating administrative issues. In general, it is confirmed that the learning model using the ensemble had higher predictive performance than the single learning model.

• Ocean Systems Engineering
• /
• v.8 no.2
• /
• pp.101-118
• /
• 2018

In case of conventional shallow-draft semisubmersibles, unacceptably large riser stroke was the restricting factor for dry-tree-riser-semisubmersible development. Many attempts to address this issue have focused on using larger draft and size with extra heave-damping plates, which results in a huge cost increase. The objective of this paper is to investigate an alternative solution by improving riser systems through the implementation of a magneto-rheological damper (MR Damper) so that it can be used with moderate-size/draft semisubmersibles. In this regard, MR-damper riser systems and connections are numerically modeled so that they can couple with hull-mooring time-domain simulations. The simulation results show that the moderate-size semisubmersible with MR damper system can be used with conventional dry-tree pneumatic tensioners by effectively reducing stroke-distance even in the most severe (1000-yr) storm environments. Furthermore, the damping level of the MR damper can be controlled to best fit target cases by changing input electric currents. The reduction in stroke allows smaller topside deck spacing, which in turn leads to smaller deck and hull. As the penalty of reducing riser stroke by MR damper, the force on the MR-damper can significantly be increased, which requires applying optimal electric currents.

• Journal of IKEEE
• /
• v.18 no.2
• /
• pp.291-297
• /
• 2014

Since hand gesture recognition was realized thanks to improved image processing algorithms, sign language translation has been a critical issue for the hearing-impaired. In this paper, we extract human hand figures from a real time image stream and detect gestures in order to figure out which kind of hand language it means. We used depth-color calibrated image from the Kinect to extract human hands and made a decision tree in order to recognize the hand gesture. The decision tree contains information such as number of fingers, contours, and the hand's position inside a uniform sized image. We succeeded in recognizing 'Hangul', the Korean alphabet, with a recognizing rate of 98.16%. The average execution time per letter of the system was about 76.5msec, a reasonable speed considering hand language translation is based on almost still images. We expect that this research will help communication between the hearing-impaired and other people who don't know hand language.