• The KIPS Transactions:PartC
• /
• v.10C no.7
• /
• pp.885-890
• /
• 2003

The Core Base Tree (CBT) multicast routing architecture is a multicast routing protocol for the internet. The CBT establishes a single shared tree for a multicast connection. The shared tree Is rooted at a center node called core. The location of the core may affect the cost and performance of the CBT. The core placement method requires the knowledge of the network topology In this Paper, we propose a simple and effective method for selecting the core. This method requires the distance vector information. in addition, we used results that calculated sample correlation coefficient. And then we select suitable routing algorithm according to member's arrangement states in muliticast group. we select core node that have minimum average cost or PIM-SM protocol is selected. The performance of this method is compared with several other methods by extensive simulations (i.e mean delay, maximum delay, and total cost). Our results shows that this method for Selecting Core is very effective.

• The Journal of Korean Society for School & Community Health Education
• /
• v.20 no.1
• /
• pp.57-68
• /
• 2019

Objectives: We would like to manage university student's health factors by researching the connection between BMI and oral health and behavior of university students. And provide basic data by integrating for weight management programs that target overweight people can improve oral health. Methods: Self-evaluation questionnaires were surveyed for 315 students who agreed to participate in the survey, using questionnaires used in the preceding study were modified and complemented. We analyzed the data with frequency analysis, descriptive statistics, t-test, chi-square test와 ANOVA, Spearman correlation coefficient by using IBM SPSS Statistics 21.0 (IBM Co., Armonk, NY, USA). The significance level for significance was set at 0.05. Results: People who smoke and alcohol drink have a lower score in their oral health behavior and oral health knowledge than those who do not. There was a significant difference between the BMI group, in the oral health behavior and oral health knowledge scores. BMI and smoking (r=0.230, p<0.001), alcohol drinking (r=0.121, p<0.05) were significant positive correlation. BMI and sleep time (r=-0.127, p<0.05), oral health behaviors (r=-0.133, p<0.001) were significant negative correlation. oral health behaviors and oral health knowledge (r=0.344, p<0.001) were significant positive correlation. Conclusion: Schools and communities will need to be educated about smoking and drinking, while at the same time developing programs that can improve oral health by integrating weight management programs.

• Journal of the Economic Geographical Society of Korea
• /
• v.11 no.3
• /
• pp.492-507
• /
• 2008

Many classical network analysis methods approach networks in aspatial perspectives. Measuring network reliability and finding critical nodes in particular, the analyses consider only network connection topology ignoring spatial components in the network such as node attributes and edge distances. Using local network autocorrelation measure, this study handles the problem. By quantifying similarity or clustering of individual objects' attributes in space, local autocorrelation measures can indicate significance of individual nodes in a network. As an application, this study analyzed internet backbone networks in the United States using both classical disjoint product method and Getis-Ord local G statistics. In the process, two variables (population size and reliability) were applied as node attributes. The results showed that local network autocorrelation measures could provide local clusters of critical nodes enabling more empirical and realistic analysis particularly when research interests were local network ranges or impacts.

• The Journal of the Korea institute of electronic communication sciences
• /
• v.18 no.1
• /
• pp.213-218
• /
• 2023

In order to use the VR HMD, operation through separate controllers in both hands is required. Methods for text input in VR include a method of selecting virtual keyboard keys on the screen one by one using a controller, a method of inputting through a keyboard that is a resource of a computer by connecting a computer and VR, or a method of inputting through a keyboard that is a resource of a computer by purchasing a wireless keyboard in VR and wireless keyboard connection method. As such, the text input method in current VR equipment causes inconvenience and additional costs to users. For these reasons, most of the VR-related contents are limited to simple functions such as games or viewers, and there is a risk that VR equipment will be recognized as a simple game machine. Therefore, in this study, a multi-input interface using hand tracking provided by the Oculus Quest2 device is designed and partially implemented. Through this, it is expected that various tasks such as document work and business processing as well as games can be conveniently used using VR equipment.

• Korean Journal of Optics and Photonics
• /
• v.27 no.6
• /
• pp.212-217
• /
• 2016

In connection-oriented data-transport services, data loss can occur when the service experiences a problem on its end-to-end path. To promptly resolve this problem, the data-switching systems providing the service should quickly modify their internal configurations distributed among different places in each system. This is performed through a sequence of problem (event) recognition, sharing, and handling procedures among multiple control processors in the system. This paper proposes a method for event sharing and messaging between control processors, to improve the time determinacy of event processing. This method simplifies runtime event sharing and minimizes the time variability caused by the event data, resulting in a decrease in the latency time in processing global events. The proposed method lessens the latency time of global event processing by about 40%, compared to general methods, for 738 internal path changes.

• Journal of the Korea Society of Computer and Information
• /
• v.14 no.7
• /
• pp.123-132
• /
• 2009

The perforrnance and portability of mobile applications can be greatly increased by adopting proxy modiles which exists between the conventional system and the device. When mobile devices collaborate with the conventional computers, there are problems to address: a battery life problem, limited input and output methods, and intermittent wireless connection. Those issues are magnified in the multimedia collaboration environment since it works in a real-time condition and the size of the message in the system is big in many cases. Additionally, because multimedia collaboration system softwares are too heavy and complex for mobile devices, it is veη hard to integrate them with conventional systems. In this paper, we describe our design and its implementation of a novel approach to map events (i.e. messages) using a proxy for mobile applications. We adopt a proxy to provide a content adaptation (i.e. transcoding) where the message contents are customized. Also, we design a mobile version publish/subscribe system to provide communication service for mobile device in loosely coupled and flexible manner. We present our empirical results which show that our design can be efficiently implemented and integrated with a conventional multimedia collaboration system.

• Journal of Gifted/Talented Education
• /
• v.21 no.4
• /
• pp.861-884
• /
• 2011

In this study, we developed and applied 15 evaluation questions about light to 30 middle school students in K University Science Education Institute for the Gifted. Then we used the theory of knowledge space and analyzed the middle school Science Gifted Students' knowledge state about light. By schematizing the hierarchy from it, we intended to not only measure students' knowledge state about light, but use it as the basic materials to improve teaching methods. To achieve the purpose of this study, we analyzed the evaluation results and individual knowledge state and hierarchy of questions. As a result, there were different knowledge structures in the individual, and we found that we should diagnose them differently. In addition, we have had implications that it has the connection with each questions and the individual knowledge state.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.5 no.3
• /
• pp.427-433
• /
• 2001

This paper proposes a web-based 3 dimensional face modeling system that makes a realistic facial model efficiently without any 30 scanner or camera that uses in the traditional methods. Without expensive image-input equipments, we can easily create 3B models only using front and side images. The system is available to make 3D facial models as we connect to the facial modeling server on the WWW which is independent from specific platforms and softwares. This system will be implemented using Java 3D API, which includes the functions and conveniences of developed graphic libraries. It is a Client/server architecture which consists of user connection module and 3D facial model creating module. Clients connect with the facial modeling server, input two facial photographic images, detects the feature points, and then create a 3D facial model modifying generic facial model with the points according to the procedures using only the web browser.

• Convergence Security Journal
• /
• v.12 no.2
• /
• pp.107-113
• /
• 2012

Recently, according to the establishment of personal information protection Act, the public and private organizations are taking a step to protect personal information rights and interests by employing the technical methods such as the access control mechanism, cryptography, etc. The result of the personal information leakage causes a serious damage for the organization image and also has to face with the responsibility by law. However, applying access control and cryptographic approach on the personal information item for every connection to large database system causes significant performance degradation in a large database system. In this paper, we designed and implemented the light weight system using JVM (Java Virtual Machine) for the Oracle DBMS environment which the concurrent transaction occurs many, thereby the proposed system provides the minimum impact on the system performance and meets the need of personal information protection. The proposed system was validated on the personal information protection system which sits on a 'A' public organization's portal site and personnel information management system.

• The KIPS Transactions:PartC
• /
• v.11C no.5
• /
• pp.677-682
• /
• 2004

In the present paper routing and wavelength assignment (RWA) in optical WDM networks is considered. Previous techniques based on the combination of integer linear programming and graph coloring are complex and require extensive use of heuristics. Such methods are mostly slow and sometimes impossible to get results due to infeasibility. An alternative approach applied to RWA employs on the greedy algorithm for obtaining the maximum edge disjoint paths. Even though this approach is fast, it produces a solution for any connection request, which is very far from the optimal utilization of wavelengths. We propose a novel algorithm, which is based on the maximum flow technique to obtain the maximum quantity of edge, disjoint paths. Here we compare the offered method with previous maximum edge disjoint paths algorithms ap plied to the RWA.