• Journal of KIISE:Information Networking
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• v.34 no.1
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• pp.62-72
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• 2007

Mobile Virtual Private Network (MVPN) provides VPN services without geographical restriction to mobile workers using mobile devices. Coexistence of Mobile IP (MIP) protocol for mobility and IPsec-based VPN technology are necessary in order to provide continuous VPN service to mobile users. However, Problems like registration failure or frequent IPsec tunnel re-negotiation occur when IPsec-based VPN Gateway (GW) and MIP are used together. In order to solve these problems, IETF proposes a mechanism which uses external home agent (x-HA) located external to the corporate VPN GW. In addition, based on the IETF proposal, a mechanism that assigns x-HA dynamically in the networks where MN is currently located was also proposed with the purpose to reduce handover latency as well as end-to-end delay. However, this mechanism has problems such as exposure of a session key for dynamic Mobility Security Association (MSA) or a long latency in case of the handover between different networks. In this paper, we propose a new MVPN protocol in order to minimize handover latency, enhance the security in key exchange, and to reduce data losses cause by handover. Through a course of simulation, the performance of proposed protocol is compared with the existing mechanism.

• Journal of Educational Research in Mathematics
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• v.17 no.1
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• pp.33-50
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• 2007

Positive attitude toward mathematics is gaining bigger recognition as an important contributing factor to mathematical ability. As a strategy for strengthening affective domain and betterment of mathematics teaching and loaming, classifying students by their causes for liking or disliking mathematics can be an effective way In this study the author tried to devise methods to classify students by their types of math disliking and investigate correlations between mathematical achievements and these math-disliking types from a sample group of 8th graders. To identify the types of reasons why 8th graders dislike mathematics, a questionnaire with 30 items was made firstly. Then by applying the 'Factor analysis' of SPSS, the 30 items were divided into five partitions. Through abstraction of each partition, five math-disliking types, 'Competences', 'Basics', 'Confidences', 'Usefulness', and 'Teachers' were defined. They are expected to help teachers for describing each student's tendency of math-disliking. Further, correlation coefficients between mathematical achievements and each of the five math-disliking type were investigated against 4 groups which were made from sample group by the discrimination of gender and two levels (high and low) of mathematical achievements in cognitive area. As results, the following facts were found. (i) The trends of correlations between cognitive achievement and the five math disliking types were different across the 4 groups at statistically meaningful degrees. (ii) Most of the male students who had math-disliking types were proved to be in the low achievement level. But for the female students, only 50% of students who had math-disliking types were in the low achievement level. (iii) Compared to male students, higher portion of female students had math-disliking types despite their high achievement in cognitive area.

• Journal of KIISE:Computing Practices and Letters
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• v.14 no.2
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• pp.246-250
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• 2008

This paper presents the design of network vulnerability analysis system which can integrate various vulnerability assessment tools to improve the preciseness of the vulnerability scan result. Manual checking method performed by a security expert is the most precise and safe way. But this is not appropriate for the large-scale network which has a lot of systems and network devices. Therefore automatic scanning tool is recommended for fast and convenient use. The scanning targets may be different according to the kind of vulnerability scanners, or otherwise even for the same scanning target, the scanning items and the scanning results may be different by each vulnerability scanner, Accordingly, there are the cases in which various scanners, instead of a single scanner, are simultaneously utilized with the purpose of complementing each other. However, in the case of simultaneously utilizing various scanners on the large-scale network, the integrative analysis and relevance analysis on vulnerability information by a security manager becomes time-consumable or impossible. The network vulnerability analysis system suggested in this paper provides interface which allows various vulnerability assessment tools to easily be integrated, common policy which can be applied for various tools at the same time, and automated integrative process.

• The Journal of the Korea Contents Association
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• v.13 no.5
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• pp.234-242
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• 2013

In 2007, Long-Term Care Insurance Law was enacted to share the family burden of caring for the elderly who are unable to perform every day living activities due to their old age and chronic diseases such as senile dementia, diabetes mellitus, stroke and more. Backed by this law, since 2008, care workers have been sent to the elderly care centers or each elder's home to help them not only with their recovery from illnesses, but also with general activities from dressing, eating, bathing, walking even to toileting. However, according to the recently released survey by National Human Rights Commission, it has been found that the caring workers are in a very poor working condition including low income, abused blanket wage system, shortage of welfare services, extra works and even sexual harrassment. It is becoming an important issue due to fast-ageing population, the fact that the care workers have had experiences of violation in their right of labor while they are at work needs to be carefully treated. In that sense, this article presents some difficulties the caring workers face and proposes effective ways to solve these problems through the perspective of human rights and human labor rights based on the report written by National Human Rights Commission. In short, for this law to function properly and to boost the worker's capability of providing better services to beneficiaries, followings can be good answers - enhanced management and supervision on caring plans and care centers, providing immediate counselling and protection for victimized care givers, training courses offered to promote service receiver's sincere respect and strengthened awareness upon care givers.

• Journal of the Korean Society of Hazard Mitigation
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• v.10 no.2
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• pp.61-68
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• 2010

Korea is constructing the disaster management system to prevent various disasters and minimize damages. In spite of these efforts, however, Korea lately suffered from a number of diverse disasters. These disasters once again lead to the questions and criticisms concerning the effectiveness of the disaster management system. So research into how to quantify the disaster management system is very significant in securing the right of the people to lead a safe life, keeping human life and properties from being injured. The purpose of this study is to prioritize policies which can be considered for establishing and operating disaster management system. To do that, this study conducts a questionnaire survey, targeting for 282 fire man. The survey includes various factors according to four stages in disaster management process: prevention, preparedness, response and recovery. The method used is AHP(Analytic Hierarchy Process) technique using expertchoice 2000. Results of the analysis are as follows. At the first stage of analysis, prevention is found as the most significant factor. The other significant factors are response, preparedness, and recovery factor in order. At the second stage of analysis, share of role among disaster facilities is the most significant factor. Reorganization of disaster facilities and connection of law are significant in order.

• The Journal of the Korea Contents Association
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• v.18 no.9
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• pp.675-683
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• 2018

As interest in eco-friendly architecture and Korean traditional culture is increasing, interest in contemporary han-ok is steadily increasing. Recently, many people experienced the han-ok directly and indirectly with the attention of a commercial contemporary han-ok such as restaurants, coffee shops, and lodging facilities, and as a result, the house has a preference for the residence of the contemporary han-ok. Compared to modern residential houses, however, han-ok is lack the convenience of heating and cooling, energy management, security, and maintenance. For this reason, the increased interest and preference for han-ok does not lead to living in contemporary han-ok. This study was conducted in the following ways to improve inconvenience by applying smart home services to contemporary han-ok. Recent technology trends in smart home services and technologies developed and marketed to date have been identified in previous research cases and literature studies. Based on this, a list of smart home services and their application methods were derived that would relieve the inconvenience of contemporary han-ok for smart home services. We hope that this research will serve as a reference for subsequent researchers studying contemporary han-ok.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.1
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• pp.92-97
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• 2018

Recently, the safety issue of high-rise concrete buildings damaged by fire, helicopter collisions, earthquakes, and faulty construction has attracted a great deal of interest. It is essential to know the strength of the concrete in order to accurately evaluate its safety for the reinforcement of these buildings. The core drilling method is considered to be the most effective method of assessing the compressive strength of concrete. However, it is very difficult to retrieve the core without the reinforcing bars, because buildings made with high-strength concrete are overcrowded with reinforcing bars. These reinforcing bars are often present in the core specimens, but there are few research studies and no regulations concerning the assessment of the strength of the concrete for high-strength core specimens within reinforcing bars. The purpose of this study is to investigate the effects of the reinforcement arrangement on the strength of the concrete and to present the quantitative values. To complete this research, the compressive strengths of different types of concrete with two different strengths (40 MPa and 60 MPa), two reinforcing bar diameters (10 mm and 12 mm), and 15 types of specimens with or without reinforcement arrangements were prepared and tested. As a result, the strength of the cylinders whose volume is less than or equal to the reinforcement volume of $53.1cm^3$ (about 4 - 13 mm) was predicted to have a low value of up to 60% of the strength of the cylinders without reinforcement.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.1
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• pp.113-120
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• 2018

Angiography and CT angiography are used widely for the examination of vascular diseases, but the diagnosis of such diseases is made mostly by the subjective judgment of the inspector. This paper proposes a method for detecting the suspicious regions of stenosis and aneurysm in the inner surfaces of 3D blood vessel models reconstructed from medical images. Initially, the 3D curve-skeletons of the blood vessel models and the contours at the nodes of the curve-skeletons were generated. Next, the 3D curve-skeletons were divided into a set of branches and the areas of normal contours of nodes located in each branch were calculated. The nodes whose contours contain suspicious regions were detected by taking into account the average area, maximum and minimum areas, and the area difference between the adjacent normal contours. The diagnosis of stenosis and aneurysm can be supported by properly visualizing the suspicious regions detected. The suspicious regions of the disease were identified by implementing and testing it using several data sets of human blood vessels, highlighting the usefulness of the proposed method.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.7
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• pp.3165-3174
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• 2012

Recently the increasingly common large refrigerator is the side by side(SBS) refrigerator whose freezing chamber and refrigerating chamber are set side by side. But one of the biggest dissatisfaction of customers about SBS refrigerator is that the two doors don't meet the same height when they are closed. It is called door height difference(DHD). The main cause of DHD is the unevenness of floor on which a refrigerator is placed or the cabinet deformation caused by long time use. When the DHD is confirmed, the customer or maintenance personnel use wrench to adjust the support screw to make the refrigerator to reach the horizontal position. But for big refrigerator, it is not only difficult for women and old people who don't have enough force to adjust it, but also inappropriate to require customers to do this job. In order to resolve this problem, this research proposes a new mechanism which can detect the DHD and adjust two doors to the same height automatically. The adjustment would be completed during opening and closing the doors, avoid needing hard operation with wrench by hand.

• Journal of KIISE:Databases
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• v.34 no.4
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• pp.343-356
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• 2007

Due to advances in position monitoring technologies such as global positioning systems and sensor networks, recent position information of moving objects has the form of streaming data which are updated continuously and rapidly. In this paper we propose an efficient trajectory maintenance method that stores the streaming position data of moving objects in the limited size of storage space and estimates past positions based on the stored data. For this, we first propose a new concept of incremental extraction of position information. The incremental extraction means that, whenever a new position is added into the system, we incrementally re-compute the new version of past position data maintained in the system using the current version of past position data and the newly added position. Next, based on the incremental extraction, we present an overall framework that stores position information and estimates past positions in the stream environment. We then propose two polynomial-based methods, line-based and curve-based methods, as the method of estimating the past positions on the framework. We also propose three incremental extraction methods: equi-width, slope-based, and recent-emphasis extraction methods. Experimental results show that the proposed incremental extraction provides the relatively high accuracy (error rate is less than 3%) even though we maintain only a little portion (only 0.1%) of past position information. In particular, the curve-based incremental extraction provides very low error rate of 1.5% even storing 0.1% of total position data. These results indicate that our incremental extraction methods provide an efficient framework for storing the position information of moving objects and estimating the past positions in the stream environment.