• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2003.05a
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• pp.274-277
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• 2003

The purpose of this study is preparing the database for conventional spinning of the steel sheets which are applied into the mechanical parts such as wheel disc and driving clutch drums. The experimental work for the conventional spinning of cylindrical typed shell has been carried out and the database for limiting spinning ratios, suing-back and thickness distributions has been obtained. The working conditions are categorized for the feeding velocity and dimension of rotating mandrel and forming roller. The results are useful to the product design of conical parts. And the present study can contribute to the improvement of industrial technology.

• Journal of the Korean Institute of Educational Facilities
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• v.9 no.2
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• pp.5-13
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• 2002

The main objective of this research is to develop an experimental educational facility management information system that will be used for maintaining existing educational facilities in the elementary, junior high, and high schools. The development is based on the nationwide development plan of the education administration information system. The system developed is accomplished by use of Map-application Information System(MAPIS), an applied commercial software that combines Geographic Information System(GIS) with existing Information and Communication Technologies(ICT) such as Database system, Multimedia methodology, and Internet system. In order to figure out the features to be improved in the system developed, the research interviewed the educational facilities management in the Ministry of Education and P Local Education Authority. The authors suggest the functional improvement of the system based on the interview results.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.11 no.1
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• pp.45-51
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• 2002

To reduce the cost and increase reliability of die and mold products, automation of the finishing (polishing) process is essential. A major element of automation is a reliable database and a knowledge base for polishing status. This paper presents a polishing expert system which can determine optimal polishing sequences and conditions by using an empirical formula and an experimental database. The simplex method was used for the curve fittings of the experimental results. Also a graphical user interface, which visualizes the optimized results, was developed.

• The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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• v.33 no.4
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• pp.114-125
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• 2020

Objectives : The aim of this study is to review the topical anesthetic effect of herbal medicine. Methods : Using domestic database(OASIS, RISS) and foreign database(Pubmed, Embase, Cochrane library, CNKI), clinical studies about efficacy of herbal medicine as topical anesthetics were searched. Only randomized controlled trials(RCT) were selected and analyzed. Results : Total 647 studies were searched. After screening process, 5 articles were selected. 2 were from Chinese database and 3 were from English database. Articles were about clinical use of herbal medicine as topical anesthetics and compare their efficacy with conventional topical anesthetics. Out of 5 articles, 4 articles used pain rating scales recorded by subjects as outcome measurement. All studies showed lower pain score in herbal medicine using groups. 4 studies showed that there was no statistically significant difference in pain score between herbal medicine using group and conventional topical anesthetics using group. Conclusions : The results suggest that topical anesthetics using herbal medicine is as effective as or maybe even more effective than conventional topical anesthetics. However, experimental design and composition of intervention were all different, which provides inaccuracy when comparing the experimental results. Also, sample sizes were small and the number of RCTs were insufficient to identify full list of herbs that have potentials to be used topical anesthetics. Further studies need to be conducted to find out potentials of herbal medicine as topical anesthetics.

• Journal of Computing Science and Engineering
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• v.4 no.2
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• pp.173-187
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• 2010

Recent technological advances in mobile communication systems have made explosive growth in the number of mobile device users worldwide. One of the most important issues in designing a mobile computing system is location management of users. The hierarchical systems had been proposed to solve the scalability problem in location management. The scalability problem occurs when there are too many users for a mobile system to handle, as the system is likely to react slow or even get down due to late updates of the location databases. In this paper, we propose a top-down clustering algorithm for hierarchical location database systems in a wireless network. A hierarchical location database system employs a tree structure. The proposed algorithm uses a top-down approach and utilizes the number of visits to each cell made by the users along with the movement information between a pair of adjacent cells. We then present a modified algorithm by incorporating the exhaustive method when there remain a few levels of the tree to be processed. We also propose a capacity constraint top-down clustering algorithm for more realistic environments where a database has a capacity limit. By the capacity of a database we mean the maximum number of mobile device users in the cells that can be handled by the database. This algorithm reduces a number of databases used for the system and improves the update performance. The experimental results show that the proposed, top-down, modified top-down, and capacity constraint top-down clustering algorithms reduce the update cost by 17.0%, 18.0%, 24.1%, the update time by about 43.0%, 39.0%, 42.3%, respectively. The capacity constraint algorithm reduces the average number of databases used for the system by 23.9% over other algorithms.

• Journal of KIISE
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• v.42 no.5
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• pp.652-663
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• 2015

Due to the popularity of location-based services, the amount of generated spatial data in daily life has been dramatically increasing. Therefore, spatial database outsourcing has become popular for data owners to reduce the spatial database management cost. The most important consideration in database outsourcing is meeting the privacy requirements and guarantying the integrity of the query result. However, most of existing database transformation techniques do not support both of the data privacy and integrity of the query result. To solve this problem, we propose a spatial data transformation scheme that utilizes the shearing transformation with rotation shifting. In addition, we described the attack models to measure the data privacy of database transformation schemes. Finally, we demonstrated through the experimental evaluations that our scheme provides high level of data protection against different kinds of attack models, compared to the existing schemes, while guaranteeing the integrity of the query result sets.

• Journal of the Korea Society of Computer and Information
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• v.25 no.4
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• pp.123-131
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• 2020

The pattern query in graph database has advantages of easy query expression and high query processing performance compared to relational database SQL. However, unlike the relational database, the graph database may not utilize the advantages of pattern query depending on modeling because the methodology for building the logical data model is not defined. In this study, in the is-a node modeling method that appears during the graph modeling process, we experiment that there is a difference in performance between graph pattern query when designing with a generalization model and designing with a specialization model. As a result of the experiment, it was shown that better performance can be obtained when the is-a node is designed as a specialization model. In addition, when writing a pattern query, we show that if a variable is bound to a node or edge, performance may be better than that of the variable of not bounded. The experimental results can be presented as an is-a node modeling method for pattern query and a graph query writing method in the graph database.

• Steel and Composite Structures
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• v.21 no.4
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• pp.921-947
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• 2016

Concrete Filled Fibre Reinforced Polymer Tube (CFFT) for new columns construction has attracted significant research attention in recent years. The CFFT acts as a formwork for new columns and a barrier to corrosion accelerating agents. It significantly increases both the strength capacity (Strength enhancement ratio) and the ductility (Strain enhancement ratio) of reinforced concrete columns. In this study, based on predefined selection criteria, experimental investigation results of 134 circular CFFT columns under axial compression have been compiled and analysed from 599 CFFT specimens available in the literature. It has been observed that actual confinement ratio (expressed as a function of material properties of fibres, diameter of CFFT and compressive strength of concrete) has significant influence on the strength and ductility of circular CFFT columns. Design oriented models have been proposed to compute the strength and strain enhancement ratios of circular CFFT columns. The proposed strength and strain enhancement ratio models have significantly reduced Average Absolute Error (AAE), Mean Square Error (MSE), Relative Standard Error of Estimate (RSEE) and Standard Deviation (SD) as compared to other available strength and strain enhancement ratios of circular CFFT column models. The predictions of the proposed strength and strain enhancement ratio models match well with the experimental strength and strain enhancement ratios investigation results in the compiled database.

• Proceedings of the KIEE Conference
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• 2002.07d
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• pp.2625-2627
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• 2002

A virtual laboratory for measurement and instrumentation must aim to realize an integrated environment. To achieve this goal, we designed and implemented a client/server distributed environment and developed a web-based virtual laboratory system for electronic circuits. The proposed virtual laboratory system is composed of four important components : Principle Classroom, Virtual Experiment Classroom, Evaluation Classroom and Overall Management System. Through our virtual laboratory, the learners will be capable of learning the concepts and theories related to electronic circuit experiments and how to operate the experimental equipments. Also, every activity occurred in our virtual laboratory is recorded on database and printed out on the preliminary report form. All of these can be achieved by the aid of the Management System. The database connectivity is made by PHP and the virtual laboratory environment is set up slightly differently for each learner. Finally, we have obtained several affirmative effects such as reducing the total experimental hours and the damage rate for experimental equipments and increasing learning efficiencies as well as faculty productivity.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2003.09a
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• pp.459-462
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• 2003

Selectivity estimation of queries not only provides useful information to the query processing optimization but also may give users with a preview of processing results. In this paper, we investigate the problem of selectivity estimation in the context of a spatial dataset. Although several techniques have been proposed in the literature to estimate spatial query result sizes, most of those techniques still have some drawback in the case that a large amount of memory is required to retain accurate selectivity. To eliminate the drawback of estimation techniques in previous works, we propose a new method called MW Histogram. Our method is based on two techniques: (a) MinSkew partitioning algorithm that processes skewed spatial datasets efficiently (b) Wavelet transformation which compression effect is proven. We evaluate our method via real datasets. With the experimental result, we prove that the MW Histogram has the ability of providing estimates with low relative error and retaining the similar estimates even if memory space is small.