• Journal of Internet Computing and Services
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• v.3 no.1
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• pp.81-90
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• 2002

Large-scale distributed applications based on Internet and client/server applications have to deal with series of problems. Load balancing, unpredictable communication delays, and networking failures can be the example of the series of problems. Therefore. sophisticated applications such as teleconferencing, video-on-demand, and concurrent software engineering require an abstracted group communication, CORBA does not address these paradigms adequately. It mainly deals with point-to-point communication and does not support the development of reliable applications that include predictable behavior in distributed systems. In this paper, we present our design, implementation and performance analysis of the group communication using the CORBA-ORB. JAVA-RML and Socket based on distributed computing Performance analysis will be estimated latency-lime according to object increment, in case of group communication using ORB of CORBA the average is 14.5172msec, in case of group communication using RMI of Java the average is 21.4085msec, in case of group communication using socket the average is becoming 18.0714msec. Each group communication using multicast and UDP can be estimated 0.2735msec and 0.2157msec. The performance of the CORBA-ORB group communication is increased because of the increased object by the result of this research. This study can be applied to the fault-tolerant client/server system, group-ware. text retrieval system, and financial information systems.

• Journal of Internet Computing and Services
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• v.10 no.1
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• pp.123-134
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• 2009

The CRM(Customer Relationship Management) is a business strategy model which can reap higher profits and can provide a competitive edge to an enterprise in today's new business environments. Early next year (2009), the Capital Market Consolidation Act will be in effect in South Korea. This is required for a qualitative growth to provide QoS (Quality of Service) and ensure growth in finance, IT industry & service. Accordingly, the securities and insurance companies, banks and other financial institutions make efforts to improve their derivative financial product and also enhance their services. In this paper we design and implement a Channel Server model for a Scalable Service Channel Server to efficiently manage the high volumes of inbound customer interactions based on the requirements of a CRM center. The proposed Scalable Service Channel Server supports integration with other third party service and standardization of multiple inbound service channels. The proposed model can be efficiently used in an inbound CRM center of any banking, finance, securities and insurance establishments.

• Journal of KIISE:Computer Systems and Theory
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• v.34 no.12
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• pp.610-617
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• 2007

Incremental checkpointing, which is intended to minimize checkpointing overhead, saves only the modified pages of a process. However, the cumulative site of incremental checkpoints increases at a steady rate over time because a number of updated values may be saved for the same page. In this paper, we present a comprehensive overview of Pickpt, a page-level incremental checkpointing facility. Pickpt provides space-efficient techniques aiming to minimizing the use of disk space. For our experiments, the results showed that the use of disk space using Pickpt was significantly reduced, compared with existing incremental checkpointing.

• KIISE Transactions on Computing Practices
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• v.23 no.6
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• pp.335-342
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• 2017

In the verification and validation procedures regarding the safety-critical software of nuclear power plants for the attainment of the requisite license from the regulatory body, it is difficult to judge the safety and dependability of the development, implementation, and validation activities through a simple reading and review of the documentation. Therefore, these activities, especially safety assurance activities, require systematic evaluation techniques to determine that software faults are acceptable level. In this study, a safety case methodology is applied in an assessment of the level and depth of the results of the development and validation of a manufacturer in its targeting of the bistable processor of a digital reactor protection system, and the evaluation results are analyzed. This study confirms the possibility of an effective supplementation of the existing safety demonstration method through the application of the employed safety case methodology.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.8 no.1
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• pp.137-149
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• 2004

A new software paradigm is required on the development of network and various service requirements. With this, many studies on a mobile agent have been made. For the execution of the mobile agent, migration is the most important factor that influences the performance of the mobile agent. In this paper we propose the method that leads to high migration efficiency in order to improve the performance. The features of our migration technique are as follows. First, the migration technique creates the dynamic itinerary that appropriately copes with the network conditions and the platform changes to improve the agent execution efficiency. Second, it perfecters an executed code to reduce the amount of the mobile data and reduces the execution time by instantiating the agent in advance. Third, it improves the execution efficiency by using the checkpoint-based recovery method that does not execute the agent again and recovers the process states even though the errors take place. Though the simulation we compare the proposed method with the existing methods. The simulation result shows that the proposed method outperform the existing methods in terms of migration.

• The KIPS Transactions:PartD
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• v.12D no.7 s.103
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• pp.993-1000
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• 2005

Recently, software quality evaluation based on ISO/IEC 9126 and ISO/IEC 14598 has been widely accepted in various areas. However, these standards for software quality do not provide practical guidelines to apply the quality model and the evaluation process of software product=5. And the qualify management in most software projects has been conducted by managing defects without applying the standards for software qualify. Thus, we present a quantitative quality evaluation approach of artifacts in the Component Based Development (CBD). Particularly, our evaluation approach allows most of the standard evaluation process and adopts a quantitative quality model which uses the weights of quality characteristics obtained through carefully selected questionnaires for stakeholder and Analytic Hierarchical Process(AHP). Moreover, we have also examined the proposed evaluation approach with applying the checklists for the artifacts of the CBD to a small-scale software project. As a result, we believe that the proposed approach will be helpful for acquiring the high quality software.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.20 no.5
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• pp.37-48
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• 2010

Designated verifier signatures allow a signer to prove the validity of a signature to a specifically designated verifier. The designated verifier can be convinced but unable to prove the source of the message to a third party. Unlike conventional digital signatures, designated verifier signatures make it possible for a signer to repudiate his/her signature against anyone except the designated verifier. Recently, two designated verifier signature schemes, Zhang et al.'s scheme and Kang et al.'s scheme, have been shown to be insecure by concrete attacks. In this paper, we find the essential reason that the schemes open attacks while those were given with its security proofs, and show that Huang-Chou scheme and Du-Wen scheme have the same problem. Indeed, the security proofs of all the schemes reflect no message attackers only. Next, we show that Huang-Chou scheme is insecure by presenting universal forgery attack. Finally, we show that Du-Wen scheme is, indeed, secure by completing its defective security proof.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.25 no.11
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• pp.1581-1587
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• 2021

As embedded system are used widely and variously, multi-edge system, which multiple edges gather and perform complex operations together, is actively operating. In a multi-edge system, it often occurs that an abnormal operation at one edge is transferred to another edge or the entire system goes down. It is necessary to determine and control edge anomalies in order to prevent system down, but this can be a heavy burden on the resource-limited edge. As a solution to this, we use power consumption data to check the state of the edge device and transmit it based on a QRcode to check and control errors at the server. The architecture proposed in this paper is implemented using 'chip-whisperer' to measure the power consumption of the edge and 'Raspberry Pi 3' to implement the server. As a result, the proposed architecture server showed successful data transmission and error determination without additional load appearing at the edge.

• Proceedings of the KSR Conference
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• 2008.11b
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• pp.1204-1212
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• 2008

This study enables to troubleshoot the problems of the existing dual system with the help of the implementation of totally dualized fault-tolerant system to L-CTC computer and HADAX, and equipments are simplified and systems are modernized with the addition of the control function, as a upgraded LCP control system, to L-CTC computer on the basis of WINDOWS based O/S switched from DOS environment. An error on Microlok, which is aninterlocking apparatus, forwarded to L-CTC computer ensures to handle the false data during the operation of the system. This paper discusses a sure way to prevent the deterioration of (SMRT) L-CYC system and to bolster its stability with formation of the dual system. Additionally, WINDOW based O/S consisting of L-CTC computer leads to simplification and modernization of facilities and enhances maintenance functions offering centralization for branch offices and machine rooms as well.

• Asia-pacific Journal of Multimedia Services Convergent with Art, Humanities, and Sociology
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• v.7 no.4
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• pp.551-559
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• 2017

In this paper, a real-time training method to improve the performance of bearing fault diagnosis. The traditional bearing fault diagnosis cannot classify a condition which is not trained by the classifier. The proposed 4-step method trains and recognizes new condition in real-time, thereby it can classify the condition accurately. In the first step, we calculate the maximum distance value for each class by calculating a Euclidean distance between a feature vector of each class and a centroid of the corresponding class in the training information. In the second step, we calculate a Euclidean distance between a feature vector of new acquired data and a centroid of each class, and then compare with the allowed maximum distance of each class. In the third step, if the distance between a feature vector of new acquired data and a centroid of each class is larger than the allowed maximum distance of each class, we define that it is data of new condition and increase count of new condition. In the last step, if the count of new condition is over 10, newly acquired 10 data are assigned as a new class and then conduct re-training the classifier. To verify the performance of the proposed method, bearing fault data from a rotating machine was utilized.