• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2008.10a
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• pp.135-138
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• 2008

The existing protocol which processes sequentially synchronization has the problem where synchronization tasks which are requested subsequently from multiple client. Should be waited for a long time. In this paper, we propose a implementation of concurrent synchronization protocol that is capable of reducing the waiting time. If there are no update conflicts among different synchronization tasks, the proposed protocol synchronizes using the multi-queue based on the round-robin scheme, in order to reduce the waiting time.

• International Journal of Advanced Culture Technology
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• v.4 no.3
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• pp.13-19
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• 2016

The growth of mobile devices in Internet of Things (IoT) leads to a number of remote and controlling system related IoT applications. For instance, home automation controlling system uses client system such web apps on smartphone or web service to access the home server by sending control commands. The home server receives the command, then controls for instance the light system. The web service gateway responsible for handling clients' requests attests an internet latency when an increasing number of end users requests submit toward it. Therefore, this web service gateway fails to detect several commands, slows down predefined actions which should be performed without human intervention. In this paper, we investigate the performance of a web server-side platgorm based event-driven, non-blocking approach called Node.js against traditional thread-based server side approach to handle a large number of client requests simultaneously for remote and controlling system in IoT remote monitoring applications. The Node.JS is 40% faster than the traditional web server side features thread-based approach. The use of Node.js server-side handles a large number of clients' requests, then therefore, reduces delay in performing predefined actions automatically in IoT environment.

• Journal of Convergence for Information Technology
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• v.9 no.1
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• pp.142-150
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• 2019

This study is a file management security system that encrypts and decrypts computer and cloud data by using Bluetooth based cryptographic module. It is a necessary solution in terms of abuse of personal information and protection of social and national information. We developed H/W and S/W for SFMS(: Safe File Management Security) related Bluetooth module in cloud environment and implemented firmware development, encryption key generation and issuance, client program for system mobile and key management system. In the terminal internal encryption and decryption, SFMS was developed to ensure high security that the hacking itself is not possible because key values exist separately for each file.

• Journal of KIISE:Databases
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• v.29 no.4
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• pp.285-296
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• 2002

When a client requests a set of data items at once, it is crucial to reduce the total time elapsed till the client receives all data items requested. This paper describes a data broadcasting technique that reduces access time for multiple data accesses from clients. The impact of the relative position of each data item in a broadcast schedule is dependent on the degree of data replication between data requests from clients. The relative broadcast frequencies for data items are affected by the degree of access skewness from clients. This paper proposes a technique for generation of a hierarchical data broadcast schedule, which can support multiple data accesses effectively by considering the data sharing among client requests and data access skewness together. Simulation results show that the proposed technique consistently performs better than the previous research results in various environments.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.46 no.6
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• pp.63-69
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• 2009

The decentralized and open characteristic of the internet, along with the mobility and portability of mobile communication, and the interactivity of the internet and mobile communications all have been grafted to enable the creation of wireless internet in our lives, bringing about a lot of change. However, existing system management software solutions show limitations in time and space, as well as problems such as uncertain error messages, and also difficulty providing swift assistance or real time emergency support. Therefore, a wireless remote control system has been designed and implemented in this thesis, which is capable of managing and monitoring remote systems using mobile communication devices (Mobile Phone, PDA, Smart Phone, Webpad) for realtime control. The implemented real time wireless remote control system provides remote server management functions, error or event message functions, log record functions, authentication function via mobile devices and system performance evaluation function classified by client transaction.

• The KIPS Transactions:PartD
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• v.11D no.5
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• pp.1149-1158
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• 2004

Today the fastest growing communities of web users are mobile visitors who browse web page with wireless PDAs and cellular phones. However, most web pages are optimiaed exclusively for desktop clients on the broadband network and are inconvenient to users with small screen mobile devices. They display only a few lines of text and cannot run client-side programs or scripts due to lack of system resource. Even worse, their connections are usually slow to support most of the data-intensive applications. In this paper, we propose a pageslet scheme that makes it feasible to browse ordinary web pages on small screen mobile devices. It extracts broadcasting sections of user preference from broadcasting web pages and automatically reorganizes the extracted sections for convenient browsing on mobile devices.

• The Journal of the Korea institute of electronic communication sciences
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• v.10 no.6
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• pp.713-720
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• 2015

As the hand-held mobile devices are widely used, they are recently coming into convergence with medical diagnostic systems. Furthermore, the wireless mobile Internet and the various kinds of communication devices are rapidly coming into wide use converging with medical technology. The mobile communication environments can make people get more health care services beyond space and time. In this paper, we implement and evaluate the mobile client and the medical diagnostic information server for transmitting, searching and updating the medical diagnostic information. The DICOM CT image and the compressed JPEG 2000 CT image are statistically evaluated by t-test performance whether those images are clinically appropriate. In the case of the DICOM CT image, we realize that the average value is relatively more appropriate to the clinical diagnosis than the JPEG 2000 CT image.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.3
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• pp.1273-1288
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• 2016

With the swift growth of wireless technologies, an increasing number of users rely on the mobile services which can exchange information in mobile networks. Security is of key issue when a user tries to access those services in this network environment. Many authentication schemes have been presented with the purpose of authenticating entities and wishing to communicate securely. Recently, Chou et al. and Farash-Attari presented two ID authentication schemes. They both claimed that their scheme could withstand various attacks. However, we find that the two authentication schemes are vulnerable to trace attack while having a problem of clock synchronization. Additionally, we show that Farash-Attari's scheme is still susceptible to key-compromise impersonation attack. Therefore, we present an enhanced scheme to remedy the security weaknesses which are troubled in these schemes. We also demonstrate the completeness of the enhanced scheme through the Burrow-Abadi-Needham (BAN) logic. Security analysis shows that our scheme prevents the drawbacks found in the two authentication schemes while supporting better secure attributes. In addition, our scheme owns low computation overheads compared with other related schemes. As a result, our enhanced scheme seems to be more practical and suitable for resource-constrained mobile devices in mobile networks.

• Journal of the Korean Association of Geographic Information Studies
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• v.16 no.1
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• pp.47-58
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• 2013

According to the increasing use of information in the mobile web environment, web information techniques previously developed considering only a specific platform become unable to use. Such techniques need to be replaced by the web standard techniques guaranteeing interoperability and to develop a new graphic user interface required in the mobile web environment. Based on such backgrounds, this paper surveyed the standards for implementing web geographic information system(GIS) service considering mobile and desktop environments. Based on the survey results, a GIS system configured with open source is designed and web mapping clients based on ExtJs are implemented for mobile and desktop environments. For the purpose of coping with the new web standard environment, the methods and prototype system suggested and implemented in the paper can be used as a case study to implement a GIS in the use of mobile and desktop environments.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2016.05a
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• pp.286-289
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• 2016

In this paper, we propose an architecture that affords mobile app based on nomadic smartphone using not only mobile cloud computing- architecture but also a dedicated web platform called Node.js built-in with the asynchronous, Nonblocking, Event-Driven programming paradigm. Furthermore, the design of the proposed architecture takes document oriented database known as MongoDB to deal with the large amount of data transmit by users of mobile web access application. The Node.js aims to give the programmers the tools needed to solves the large number of concurrent connections problem. We demonstrate the effectiveness of the proposed architecture by implementing an android application responsible of real time analysis by using a vehicle to applications smart phones interface approach that considers the smartphones to acts as a remote users which passes driver inputs and delivers output from external applications.