• Proceedings of the Korea Information Processing Society Conference
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• 2011.11a
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• pp.1082-1084
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• 2011

최근 스마트폰의 보급률이 급격하게 증가함에 따라 스마트폰 사용자들이 요구하는 어플리케이션들도 더욱 다양해지고 어플리케이션들의 효율성 또한 높아져야하는 상황이다. 또한 대부분의 스마트폰 어플리케이션들이 데이터를 효율적으로 저장, 관리하기 위해서 DataBase를 이용하고 있다. 비록 하드웨어기술이 눈부시게 발전하기는 했지만, 아직까지는 제한적인 스마트폰 기기의 하드웨어 환경상 효율적인 어플리케이션을 개발하기 위해서는 DataBase를 효율적으로 설계하고 각종 쿼리문을 적절하게 활용하여 최적의 성능을 제공할 수 있도록 구현되어야 한다. 따라서 본 연구는 변경사항이 적은 Data는 SQLite를 이용하여 스마트폰 어플리케이션 내부의 DataBase에 저장하고, 변동이 잦은 Data는 별도의 Server DataBase를 이용하여 스마트폰과의 네트워크 통신을 이용한 연동을 통해 어플리케이션의 내용이 업데이트 되도록 설계하였다.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.16 no.1
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• pp.69-75
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• 2016

The performance of a web application is an essential issue to provide high quality of the services in interactive web environments. On a sudden increase in traffic in a very short span of time, the servers became CPU starved and would become unresponsive. This would lead to a bad experience for the clients of web service. This paper deals with the effects of two configurable software settings of J2EE application servers: the maximum size of the thread pool and the maximum size of database connection pool. In order to figure out the optimum configuration value, this paper builds experimental evaluation method for web performance analysis. Finally, a case study related with the proper experimental method is presented with performance result.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.7 no.4
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• pp.638-645
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• 2003

In existing internet, e-mail protocols including POP3 and IMAP4, provide e-mail services fir exchanging messages with texts, hypertext and images as well. For the e-mail services in wireless mobile network, mobile e-mail service providers have to install a mobile exclusive e-mail server or have to convert e-mail to mobile exclusive e-mail with wireless application format in case of POP3 protocol. In the e-mail service of IMAP4 case known as web-mail, it is difficult to view e-mail directly from server without IMAP4 mobile client because e-mail is stored in mail server side with remote file server. In either case, it also has the problems of viewing the e-mail of hypertext and image information at mobile. This paper provides e-mail extraction engine with image and hypertext conversion facilities that can be applied in wireless mobile internet and it is optimized in mobile communication environments such as a small display, small size of memory with web-mail protocol based on IMAP4 as well as POP3 mail protocol.

• The KIPS Transactions:PartB
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• v.9B no.5
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• pp.533-540
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• 2002

We can buy products everywhere from Web-based shopping mall using desktop, cellular phone or PDA. To guarantee the various services for different equipment, shopping mail systems should allow a lot of different size or quality of images to provide a good service to their customers. Despite of same product image, each shopping mall saves the image in its storage space individually. Furthermore, all the product images in each shopping mall are stored as images of different quality. It may waste resources of shopping mail server and bring us developmental overhead. It is difficult to update all the images for product that is used by distributed e-catalog in everywhere. In this paper, we extended the proposed Web Image Server (WIS) for sharing one image with all clients and processing Image dynamically, so that we strengthened the function of managing shopping mall as a client of WIS and added the function of recording clients'log file and image catalog for shopping mall. We measured the response time from WIS and conventional e-Commerce site using by WAS which is one of the stress test tools for Web application. Furthermore, we measured WIS responses image requests in reasonable time when the current user is increased.

• Proceedings of the Korea Multimedia Society Conference
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• 2003.05b
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• pp.628-634
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• 2003

In existing internet, e-mail protocols including POP3 and IMAP4, provide e-mail services for exchanging messages with texts, hypertext and images as well. For the e-mail services in wireless mobile network, mobile e-mail service Providers have to install a mobile exclusive e-mail server or have to convert e-mail to mobile exclusive e-mail with wireless application format in case of POP3 protocol. In the e-mail service of IMAP4 case known as web-mail, It is difficult to view e-mail directly from server without IMAP4 mobile client because e-mail is stored in mail server side with remote file server. In either case, it also has the problems of viewing the e-mail of hypertext and image information at mobile, This Paper Provides e-mail extraction engine with image and hypertext conversion facilities that can be applied in wireless mobile internet and it is optimized In mobile communication environments such as a small display, small size of memory with web-mail protocol based on IMAP4 as well as POP3 mail protocol.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.8 no.7
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• pp.2512-2531
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• 2014

We propose a new Distributed Denial of Service (DDoS) defense mechanism that protects http web servers from application-level DDoS attacks based on the two methodologies: whitelist-based admission control and busy period-based attack flow detection. The attack flow detection mechanism detects attach flows based on the symptom or stress at the server, since it is getting more difficult to identify bad flows only based on the incoming traffic patterns. The stress is measured by the time interval during which a given client makes the server busy, referred to as a client-induced server busy period (CSBP). We also need to protect the servers from a sudden surge of attack flows even before the malicious flows are identified by the attack flow detection mechanism. Thus, we use whitelist-based admission control mechanism additionally to control the load on the servers. We evaluate the performance of the proposed scheme via simulation and experiment. The simulation results show that our defense system can mitigate DDoS attacks effectively even under a large number of attack flows, on the order of thousands, and the experiment results show that our defense system deployed on a linux machine is sufficiently lightweight to handle packets arriving at a rate close to the link rate.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.27 no.10C
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• pp.912-920
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• 2002

As computer systems and communication technologies develop rapidly, CSCW(Computer Supported Collaborative Work) system appears nowadays, through which it is available to work on virtual space without any restriction of time and place. Most of CWCS systems depend on a special network and groupware. The systems of graphics and CAD are not so many because they are specified by hardware and application software. We propose a Web-based collaborative CAD system which is independent from any platforms, and develop a 3D solid modeler in the system. This system can be worked in the environment of Client/Server architecture. Clients connect to the design server through Java applet on WWW. The server is implemented by Java application.

• Journal of Power Electronics
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• v.10 no.6
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• pp.611-620
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• 2010

This paper presents a new architecture, called "Power Electronics Remote Wiring and Measurement Laboratory (PermLAB)", that translates a common gateway interface (CGI) string from a remote web user to a web server connected to a 3-dimension switching matrix board, can be used to switch on and off, and to control a cluster of instruments and components. PermLAB addresses real-time connection, switching, and data acquisition over the Internet instead of using simulated data. A software procedure uses a signature system to identify each instrument and component in a complex system. The Web-server application is developed in HTML, JavaScript and Java, and in C language for the CGI interface, which resides in a controller portion of LabVIEW. The LabVIEW software fully integrates the Web sever, LabVIEW data acquisition boards and controllers, and the 3-dimensional switching matrix board. The paper will analyze a half-wave rectifier (AC - DC converter) circuit connected over the Internet using the PermLAB. PermLAB allows students to obtain real data by real-time wiring of real circuits in the laboratory using a "virtual breadboard" on the Web. The software for the Web-based 3-dimensional system is flexible, portable, can be integrated into many laboratory applications or expanded, and easily accessible worldwide.

• Journal of Internet Computing and Services
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• v.4 no.1
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• pp.67-74
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• 2003

According to change of software development technique as design pattern, component based development etc.., web server development part is applied activity to fit in various user requirement. Especially, EJB as sewer side component model much researches and introduce by easy and various development support. Also, component composing techniques is receiving many interests by easy and efficient application way that architecture based C2 style architecture with message handling. But, in case of EJB component that can not cail thread, C2 framework modification is unavoidable for component composition by C2 style architeccture. For this, we propose techniques to use Adapter pattern to be one of structure pattern among pattern. That is, did so that component composition by C2 style architecture may can consist changing to be able to call thread function in EJB by Adapter pattern.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2003.05a
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• pp.273-276
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• 2003

In this study, Automatic Speech Recognition Application System is designed and implemented to realize transformation from present GUI-centered web services to VUI-centered web service. Due to ASP's restriction with web in speed and implantation, in this study, Automatic Speech Recognition Application System with Java beans Component Architecture is devised and studied. Also the voice web browsing which is able to transfer voice and graphic information simultaneously is studied using Remote AWT(Abstract Windows Toolkit).