• Journal of the Korea Institute of Information and Communication Engineering
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• v.7 no.8
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• pp.1726-1731
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• 2003

The firewall is generally used to protect the internal information system from intruders and hackers who attack through the Internet. However, it is very difficult for a user to verify the performance of the firewall as well as the difference of the performance for the operating mode such as Bridge Mode and Gateway Mode. In this paper, the performance of a firewall on the operating systems or windows 2000, Linux, and FreeBSD is compared. Finally, The performance of a firewall on the FreeBSD is compared at different operating modes and the effect of the number of rules by testing throughput of a firewall is analyzed.

• Korean journal of communication and information
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• v.46
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• pp.556-589
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• 2009

With the advent of the so-called Web 2.0 age, the interconnections of various contents on the web, as well as the user-participatory services from blogs, web-based communities, picture sharing sites, and social networking sites, to the sites for collective knowledge productions, have been further vitalized. As the User Generated Contents(UGCs) are flourishing on the web, they have channeled users' desires for self-expression and social acknowledgement, and yet have created the new kinds of invasion of privacy. This study attempts to look at how the networked individuals' everyday perceptions of privacy have been reconstructed in the age of Web 2.0. By investigating how users have used the UGCs for their sociality on the web and how they have set the boundaries of the private and the public in these public or semi-public disclosures of self-expressions, it has traced the changing perceptions of privacy in everyday communication practices. For this study, it has interviewed Korean youngsters in their 10s and 20s who have grown up with the Internet and have received self-expressions and social communication on the web as everyday activities. Based on their interviews, it inquires into the concurrent notion of privacy and discuss its cultural implications.

• The Transactions of the Korea Information Processing Society
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• v.2 no.4
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• pp.567-580
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• 1995

A transition-based Objet-oriented programming system(TOPS) is a transition-based object-oriented system suitable for development of various concurrent systems.A TOPS consists of a collection of interacting structural active objects(SAOs),and their behaviors are determined by the transition statements provided in their class definitions.Furthermore,SAOs can be structurally and hierarchcally composed from their component SAOs like hardware commponents. These features allow SAOs to model components for circuit simulation more naturally than passive objects used in ordinary object-oriented programming. Also,we can easily add new kinds of components by using the inheritance mechanism.Executions of transition statements may be eventand/or time-driven, and hence digital,and mixed-mode simulation is possible.Prototype simulation programs with graphical user interfaces have been developed as TOPS progrms for digital,analog,and mixed-mode circuit simulation.

• Journal of Korea Game Society
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• v.18 no.2
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• pp.27-36
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• 2018

In this paper, we propose a win-win network operating platform for mobile games. The characteristics of the service structure suggested is to form a marketing network that can influence the mobile game market by linking with the mobile game industry, and the excellent game content of the game developer in the industrial complex may not disappear. We also would like to propose a network operating platform that would help it enter the market area steadily. The proposed platform technology is used to distribute rapidly through a win-win network between game companies and publishers. When new games are commercialized, they can support continuous target marketing through various data indicators and analytics by the developed platform. In particular, G-Cross marketing strategy is considered to be a low-cost, high-efficiency marketing method in that it can provide users with information about new games by utilizing the given game infrastructure and utilize the user group possessed by each game company.

• Journal of KIISE:Software and Applications
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• v.26 no.9
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• pp.1061-1072
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• 1999

한 개 이상의 사이트에 공간 데이타가 중복 저장된 분산 공간 DB에서, 동시에 수행될 수 있는 긴 트랜잭션의 변경은 일관성 제어를 위해 다른 사이트에 전파되어야 한다. 이때 같은 영역의 공간 데이타를 서로 다른 사이트에서 동시에 변경할 경우, 변경 상충 문제가 발생하거나 잠금 기법에 의한 오랜 대기 시간이 초래되는 문제가 있다. 또한 공간 객체는 잠금의 대상이 아닌 공간 관련성에 의한 종속성을 가진다.이 논문은 긴 트랜잭션으로 중복된 공간 데이타를 변경할 경우 중복 제어를 위한 변경 전파와 동시성 제어 문제를 다룬다. 중복된 공간 데이타의 변경 병렬성을 향상시키기 위해 영역 잠금 및 SR-bound WRITE 잠금 기법을 제시한다. 한 사이트에서 수정하는 객체들과 다른 사이트에서 수정하는 객체들 사이에 공간 관련성에 의한 종속성이 없을 경우 병렬 수정을 허용하도록 제어하며, 공간 관련성에 의한 종속성이 있을 경우 SR-based 2PC라 불리는, 확장된 2단계 완료 프로토콜로 협동작업을 수행해서 변경 상충을 해결하는 새로운 중복 제어 기법을 설계하고 구현한다.Abstract The update of a long transaction should be propagated to the other sites for consistency control, when spatial database are replicated at multiple sites to achieve availability, reliability, and performance. When the replicated spatial data are updated at the same time, the update of one site would be conflicted with the other or a user would not be able to access the replicated spatial data under the control of locking. Two spatial objects having spatial relationships should be cooperatively updated even if there are no conflicts of locking for them.This paper deals with the issues of concurrency control and update propagation of replicated spatial data. We present the concept of region lock and SR-bound WRITE lock for enhancing the parallelism of updating the replicated spatial data. If there are no spatial relationships between one site's objets and the other's objects, parallel update would be allowed. Concurrent update of two spatial objects having spatial relationships should be propagated and cooperated by using an extended two-phase commit protocol, called spatial relationship-based 2PC.

• The Transactions of the Korea Information Processing Society
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• v.4 no.12
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• pp.2971-2984
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• 1997

In this paper, we propose an efficient video block Placement scheme that utilize the current disk product that has MZR disk characteristic and users' skewed access pattern on VOD. Also, we evaluate its performance through simulation and modeling of VOD server. The basic placement rule is to place on MZR disks by LP, SHP methods according to the Zipf distribution of popularity. To verify the proposed scheme, we examined its performance on workstation with 2 MZR disks under varied skewed factors. The proposed placement scheme showed better response time than the random method. To extend proposed placement scheme to disk group, we analyzed the theoretical maximum numbers of concurrent users and the required buffer size per user. For performance parameters for the proposed scheme, we considered the disk head scheduling methods, the placement methods and the striping unit. The result of experiments showed that the proposed scheme was effective.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.27 no.1C
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• pp.90-95
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• 2002

Though the FTP(File Transfer Protocol) has been used widely and stable, It has the structural weakness that can't support current file transmissions so that we have to wait the completion of previous file transmission when try to transmit another file. If try to transmit multiple files concurrently using this FTP, It has to forking multiple FTP servers and clients in each user's PC and ISP's host machine it would result in the waist of memory, resource of network and the high workload of system. In order to solving previous problem, in this paper I have designed the new model of FTP which based on multi-thread and created NFTP(Next-Generation FTP)protocol so that may reduce the workload of system and support current file transmission effectively. I have implemented NFTP and also applied to real service, as a result It have provided reliable service by reducing the workload of system and saved the waiting time which would happened.

• Journal of Fashion Business
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• v.22 no.3
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• pp.122-142
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• 2018

In the virtual fitting system, the use of a 3D avatar is not a simple garment model, but it should be able to reproduce the size and shape of the customer using a fitting system. Although various virtual fitting systems have their own 3D avatar sizing systems and provide 3D avatars that match the size of the customer, there are limitations in realizing the actual body shape in actual use by the consumer. The purpose of this study is to realize a 3D avatar with excellent size and conformity for customer use. Therefore, this study aims to provide basic data for the formation of a 3D standard avatar of Korean women aged in their 20's, by comparing and analyzing the degree of the consumer user friendly system change of a body type, and the consumer's ability in selecting a consumer representative body type. Based on the survey data of 'Size Korea' conducted from 2004 to 2015 at three times, we examined the change of body shape over 10 years. Then, based on the results of 6th and 7th data, 4 factors of the concurrent body shape change of women of the consumer demographic studied were selected through the use of a factor analysis. Following this analysis, the 4 extracted factors were clustered again and finally released 7 representative body types, which were obtained based on height and weight. The size of each representative figure is derived by the use of a regression analysis, and it is used as a basic data for 3D avatar formation of the virtual fitting system.

• Journal of the Korea Society of Computer and Information
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• v.16 no.8
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• pp.11-18
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• 2011

The increasing of web users load to the excessive transmission traffic and system overload problems. To solve these problems, cluster systems are studied. In conventional cluster systems, when the request size is large owing to such types as multimedia and CGI, the particular server load and response time tend to increase even if the overall loads are distributed evenly. In this paper, we consider the methodology of efficient resource usage, specially distributed web cluster system. We develope an algorithm that distributes the load on the web cluster system to use the system resources, such as system memory equally. The response time is chosen as a performance measure on the various clustering models. And based on the concurrent user to the web cluster system, the response time is also examined as the number of users increases. Simulation experience with this algorithm shows that the response time and average throughput seems to have a good results compare to those with the other algorithm.

• Journal of KIISE
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• v.43 no.9
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• pp.1015-1025
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• 2016

Currently, software testing is becoming increasingly important in the industrial field and a large body of research supports the improvement of efficient software testing. Model-based testing is generally used to formalize user requirement data for test design. Complex system that includes loop and concurrency has a high probability of path explosion problem. Specially, as threads are added to concurrency, test scenarios have also increased exponentially. However, it is difficult to solve this problem using existing techniques. In this paper, we propose novel path-search technique that focuses on behavioral features of concurrency path in order to avoid path explosion problem. A system that contains concurrent paths is represented by activity diagram in case study section. Efficiency of our study is shown through comparison with several generated test scenarios of other studies. The result indicate that our approach is efficient for finding faults in loop and concurrency with fewer test scenario.