• The Journal of Korean Institute of Communications and Information Sciences
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• v.27 no.5C
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• pp.399-410
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• 2002

Web cache, which is functionally another word of proxy server, is located between client and server. Web cache has a limited storage area although it has broad bandwidth between client and proxy server, which are usually connected through LAN. Because of limited storage capacity, existing objects in web cache can be deleted for new objects by some rules called replacement algorithm. Hit rate and byte-hit rate are general metrics to evaluate replacement algorithms. Most of the replacement algorithms do satisfy only one metric, or sometimes none of them. In this paper, we propose two replacement algorithms to achieve both high hit rate and byte-hit rate with great satisfaction. In the first algorithm, the cache is appropriately partitioned according to file types as a basic model. In the second algorithm, the cache is composed of two levels; the upper level cache is managed by the basic algorithm, but the lower level is collectively used for all types of files as a shared area. To show the performance of the proposed algorithms, we evaluate hit rate and byte-hit rate of the proposed replacement algorithms using the trace driven simulation.

• Journal of Digital Contents Society
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• v.2 no.1
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• pp.73-79
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• 2001

Most of the existing algorithms try to disseminate the multimedia contents of internet service provider(ISP), without taking into account the needs and characteristics of specific websites including e-learning systems with web-based .educational contents. Sometimes the client must select the best one among the replicated repositories. However, this is a less reliable approach because clients' selections are made without prior information on server load capacity. In this paper we propose an agent system inspired by the need of improving QoS of delivering web-based educational multimedia contents without incurring long access delays. This agent system consists of three components, Analyzer, Knowledge Base, and Automaton embedded the capacity algorithm. It analyzes and investigates traffic information collected from individual replicated server by learners' requests, and selects a server which is available and is expected to provide the fastest latency time and the lowest loaded capacity, and achieves high performance by dynamic replicating web resources among multiple repositories.

• Journal of Information Processing Systems
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• v.13 no.4
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• pp.731-751
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• 2017

The burgeoning distribution of smartphone web applications based on various mobile environments is increasingly focusing on the performance of mobile applications implemented by JavaScript and HTML5 (Hyper Text Markup Language 5). If application software has a simple functional processing structure, then the problem is benign. However, browser loads are becoming more burdensome as the amount of JavaScript processing continues to increase. Processing time and capacity of the JavaScript in current mobile browsers are limited. As a solution, the Web Worker is designed to implement multi-threading. However, it cannot guarantee the computing ability as a native application on mobile devices, and is not sufficient to improve processing speed. The method proposed in this research overcomes the limitation of resources as a mobile client and guarantees performance by native application software by providing high computing service. It shifts the JavaScript process of a mobile device on to a cloud-based computer server. A performance evaluation experiment revealed the proposed algorithm to be up to 6 times faster in computing speed compared to the existing mobile browser's JavaScript process, and 3 to 6 times faster than Web Worker. In addition, memory usage was also less than the existing technology.

• The KIPS Transactions:PartA
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• v.10A no.6
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• pp.635-642
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• 2003

The radical development of recent network technology provides the basic foundation which can establish a high speed and cheap cluster system. It is a general trend that conventional cluster systems are built as the system over a fixed level based on stabilized and high speed local networks. A multi-distributed web cluster group is a web cluster model which can obtain high performance, high efficiency and high availability through mutual cooperative works between effective job division and system nodes through parallel performance of a given work and shared memory of SC-Server with low price and low speed system nodes on networks. For this, multi-distributed web cluster group builds a sub-cluster group bound with single imaginary networks of multiple system nodes and uses the web distributed shared memory of system nodes for the effective data transmission within sub-cluster groups. Since the presented model uses a load balancing and parallel computing method of large-scale work required from users, it can maximize the processing efficiency.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.5
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• pp.150-164
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• 2013

Currently it is being gradually focused on the mobile application's processing performance implemented by Javascript and HTML (Hyper Text Markup Language) due to the dissemination of mobile web application supply based on the WAC (Wholesale Application Community). If the application software has a simple functional processing structure, then the problem is benign, however, the load of a browser is getting heavier as the amount of Javascript processing is being increased. There is a limitation on the processing time and capacity of the Javascript in the ordinary mobile browsers which are on the market now. In order to solve those problems, the Web Worker that is not supported from the existing Javascript technology is now provided by the HTML 5 to implement the multi thread. The Web Worker provides a mechanism that process a part from the single thread through a separate one. However, it can not guarantee the computing ability as a native application on the mobile and is not enough as a solution for improving the fundamental processing speed. The Cyclostorm overcomes the limitation of resources as a mobile client and guarantees the performance as a native application by providing high computing service and ascripting the Javascript process on the mobile to the computer server on the cloud. From the performance evaluation experiment, the Cyclostorm shows a maximally 6 times faster computing speed than in the existing mobile browser's Javascript and 3 to 6 times faster than in Web Worker of the HTML 5. In addition, the usage of memory is measured less than the existing method since the server's memory has been used. In this paper, the Cyclostorm is introduced as one of the mobile cloud computing services to conquer the limitation of the WAC based mobile browsers and to improve the existing web application's performances.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.8B
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• pp.786-796
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• 2009

Currently, web syndication is usually utilized in desktop environments, but not considering mobile environments. In this paper, we focus on the extension of the desktop based web syndication to the mobile internet. Simply adapting the desktop based web syndication to mobile devices can cause high wireless internet communication cost. We propose PMS(Proxy-based Mobile Syndication) model which achieves low cost mobile syndication. In the PMS model, MWProxy is defined as a proxy server between mobile devices and web sites. It can reduce the communication cost by peeking up modified items from the web sites and reducing the channel size. In this paper, we designed and implemented the PMS system in a mobile phone and evaluated the performance of the PMS system by conducting real experiments using mobile emulators.

• International Journal of Internet, Broadcasting and Communication
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• v.13 no.1
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• pp.54-60
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• 2021

AR (Augmented Reality) is a technology that provides virtual content to the real world and provides additional information to objects in real-time through 3D content. In the past, a high-performance device was required to experience AR, but it was possible to implement AR more easily by improving mobile performance and mounting various sensors such as ToF (Time-of-Flight). Also, the importance of mobile augmented reality is growing with the commercialization of high-speed wireless Internet such as 5G. Thus, this paper proposes a system that can provide AR services via GNN (Graph Neural Network) using cameras and sensors on mobile devices. ToF of mobile devices is used to capture depth maps. A 3D point cloud was created using RGB images to distinguish specific colors of objects. Point clouds created with RGB images and Depth Map perform downsampling for smooth communication between mobile and server. Point clouds sent to the server are used for 3D object detection. The detection process determines the class of objects and uses one point in the 3D bounding box as an anchor point. AR contents are provided through app and web through class and anchor of the detected object.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.1
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• pp.140-145
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• 2009

Recently, lots of research activities have been carried out to provide advanced smart control functions applying a computer networking technology to telemeter/telecontrol systems. In this paper, we suggest client/server architecture with specially designed remote and local control software for applicant those to greenhouse model. The server system collects and integrates various datas related sensor or actuator, and stores in database maintaining high quality of remote I/O control operation. Where as the client system simply operation such as control panel on the internet web browser. Implemented system well communicate interactively both monitoring and control status of greenhouse including multimedia informations. In this study we also analyze the extent of the performance enhancement in terms of overall throughput and data transfer time effected by packet size.

• International Journal of Contents
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• v.11 no.1
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• pp.41-51
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• 2015

Management systems for electronic library have been developed on the basis of Client/Server or ASP framework in domestic market for a long time. Therefore, both service provider and user suffer from their high cost and effort in management, maintenance, and repairing of software as well as hardware. Recently in addition, mobile devices like smartphone and tablet PC are frequently used as terminal devices to access computers through the Internet or other networks, sophisticatedly customized or personalized interface for n-screen service became more important issue these days. In this paper, we propose a new scheme of integrated management system for electronic library based on SaaS and Web Standard. We design and implement the proposed scheme applying Electronic Cabinet Guidelines for Web Standard and Universal Code System. Hosted application management style and software on demand style service models based on SaaS are basically applied to develop the management system. Moreover, a newly improved concept of duplication check algorithm in a hierarchical evaluation process is presented and a personalized interface based on web standard is applied to implement the system. Algorithms of duplication check for journal, volume/number, and paper are hierarchically presented with their logic flows. Total framework of our development obeys the standard feature of Electronic Cabinet Guidelines offered by Korea government so that we can accomplish standard of application software, quality improvement of total software, and reusability extension. Scope of our development includes core services of library automation system such as acquisition, list-up, loan-and-return, and their related services. We focus on interoperation compatibility between elementary sub-systems throughout complex network and structural features. Reanalyzing and standardizing each part of the system under the concept on the cloud of service, we construct an integrated development environment for generating, test, operation, and maintenance. Finally, performance analyses are performed about resource usability of server, memory amount used, and response time of server etc. As a result of measurements fulfilled over 5 times at different test points and using different data, the average response time is about 62.9 seconds for 100 clients, which takes about 0.629 seconds per client on the average. We can expect this result makes it possible to operate the system in real-time level proof. Resource usability and memory occupation are also good and moderate comparing to the conventional systems. As total verification tests, we present a simple proof to obey Electronic Cabinet Guidelines and a record of TTA authentication test for topics about SaaS maturity, performance, and application program features.

• Journal of Korea Multimedia Society
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• v.4 no.6
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• pp.534-542
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• 2001

Recent content-based image retrieval systems make use of a local single server contained a limited number of images. So these systems are not satisfactory for the Web user's needs that make request for various images on the Web. A content-based image retrieval system that has regard for a great number of Web images has to stand on the basis of real-time first of all. Therefore, to implement the above system we have to resolve a problem of large waste time to take for an image collection and feature extractions. In recent, PC clusters with a load distribution are implemented for the purpose of high-performance data processing. In this paper, we decreased the whole retrieval time by distributing the tasks of image collection and feature extraction to take much time among the slave computers of the PC cluster, and so we found the possibility of the real-time processing in the retrieval of Web images.