• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.3C
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• pp.195-204
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• 2007

The cyclic redundancy check(CRC) code used to decide retransmission request in hybrid automatic repeat request(HRAQ) system can also be used to stop iterative decoding of turbo code if it is used as an error correcting code(ECC) of HARQ system. Thus a scheme to use CRC code for both iteration stop and repeat request in the HARQ system with turbo code based on the standard of cdma 2000 system is proposed in this paper. At first, the optimum CRC code which has the minimum length without performance degradation due to undetected errors is found. And the most appropriate turbo encoder structure is also suggested. As results, it is shown that at least 32-bit CRC code should be used and a turbo code with 3 constituent encoders is considered to be the most appropriate one.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.4
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• pp.787-793
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• 2015

In order to support reliable medium access control (MAC) layer multicast services in Broadband Wireless Access (BWA) networks, we here propose spreading codes (Cumulative ACK (CA) code and ARQ Feedback Request (AFR) code) based reliable multicast feedback scheme. The status indications based on the automatic repeat request (ARQ) mechanism are needed in some multicast services. In accordance with various wireless channel environments, we demonstrate the performance excellency of our proposed scheme with respect to required uplink resources compared with the original feedback scheme based on unicast ARQ feedback messages. In addition, we analyze packet error rate (PER) against the various wireless channel environments.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.14 no.4
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• pp.1-6
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• 2014

This paper proposes a mobile content curation service to collect various online/offline publications. The company publishes one-time topic information to a broker server in advance and customer curates topic information on a mobile device by requesting it. The main characteristics of the proposed service are: it is based on request/response model rather than existing publish/subscribe model, can easily specify topic information by input string without QR code or audio recognition, and retrieves all of topic information anywhere anytime by storing it on mobile device. This service can be used for second screen campaign for TV and various online/offline events.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.9B
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• pp.610-618
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• 2005

As developed Internet and Computer Capability, Many Users take the many information through the network. So requirement of User that use to network was rapidly increased and become various. But it spend much time to accept user requirement on current network, so studied such as Active network for solved it. This Active node on Active network have the capability that stored and processed execution code aside from capability of forwarding packet on current network. So required execution code for executed packet arrived in active node, if execution code should not be in active node, have to take by request previous Action node and Code Server to it. But if this execution code take from previous active node and Code Server, bring to time delay by transport execution code and increased traffic of network and execution time. So, As used execution code stored in cache on active node, it need to increase execution time and decreased number of request. So, our paper suggest ANC caching technique that able to decrease number of execution code request and time of execution code by efficiently store execution code to active node. ANC caching technique may decrease the network traffic and execution time of code, to decrease request of execution code from previous active node.

• Proceedings of the KOSOMBE Conference
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• v.1992 no.05
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• pp.118-120
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• 1992

We have developed and been using laboratory order communication system which is a computerized laboratory request and reception system wi th bar code between inpatient or outpatient and the clinical laboratory in Chungbuk National Unversity Hospital. Work flows are as follows: Tests are requested by the physicians through hospital information system without issuing request forms. Bar code stickers containing demographics of patient and other informations such as sample number, slip code and specimen code are printed and attached to smaple tubes. At the department of clinical pathology, smaples are received through the bar code reader. Area numbers are automatically created and laboratory work numbers are determined. Worklists can be issued by each section of laboratory when needed. Our order communication system alleviates the human labor such as specimen labelling and making worklist and reduces clerical errors that occur from sample collection to laboratory analysis.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.3
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• pp.543-548
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• 2016

Public electronic certificates, as an important means for identification, have been used as the main economic transactions, including banking, e-government, e-commerce. identification. However, damage cases of certificates have been increased by Illegally issued and by hacking practices. Also the users have a difficult in ensuring that their certificates when and where to use. Therefore, the proposed system gives the organization code for the Institutions using OCSP services in advance, the organization code embedded in extensions of OCSP request message structure when institutions ask the validation of certificate to CA(Certificate Authority). Also, OCSP server can extract the organization code from OCSP request message, confirm the institution, and record it in certificate history management table of DB. In this paper, we presented a system that could determine the certificate history check using OCSP service, public electronic certificate validation service, and implemented to prevent and cope immediately with financial incidents.

• Proceedings of the IEEK Conference
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• 2003.07a
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• pp.43-48
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• 2003

This paper presents a comparative evaluation of a modified version (A-Protocol) of the Distributed-Queueing Request Update Multiple Access (DQRUMA)Multi-Code Code Division Multiple Access (MC-CDMA) protocol and an enhanced version (P-Protocol) of the DQRUMA/MC-CDMA protocol with a lattice pool for request accesses (LPRA) scheme in a packet-based voice traffic environment. Analytical results agree with the simulation ones and show that the P-Protocol outperforms the A-Protocol in terms of the packet loss rate for voice traffic.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.4
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• pp.642-649
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• 2018

The Modbus protocol is the most widely used protocol for connecting multiple slave control units (SCUs) in the master control unit. However, the Modbus protocol does not identify which SCU response message corresponds to the service request message. Therefore, when using the Modbus protocol, one service request message can be transmitted after processing the previous message. In this paper, we propose a Modbus application protocol with an index code and a service code to solve the problem. As a result of experimentation, it is possible to transmit the next service request message without processing the previous service request message. And when a communications error occurs, it is possible to identify what type of error occurred using an error detection algorithm. Also, with simultaneous multiple service requests, the proposed protocol can improve processing time by about 66.2%, compared to the original Modbus protocol.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.4C
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• pp.370-378
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• 2007

The most appropriate low density parity check (LDPC) code for hybrid automatic repeat request (HARQ) system suitable for future multimedia communication systems is presented in this paper. HARQ system with punctured LDPC code is investigated at first. And two transmission schemes with parallel concatenated LDPC code are also presented and their performances are analyzed according to the various values of mean column weight (MCW). As a result, the parallel concatenated LDPC code with the diversity effect of information bit is considered to be more appropriate for HARQ system considering the throughput as well as error performance.

• Journal of KIISE
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• v.44 no.1
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• pp.1-12
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• 2017

The continuously growing internet service requirements has resulted in a multitier system structure consisting of web server and database (DB) server. In this multitier structure, the existing intrusion detection system (IDS) detects known attacks by matching misused traffic patterns or signatures. However, malicious change to the contents at DB server through hypertext transfer protocol (HTTP) requests at the DB server cannot be detected by the IDS at the DB server's end, since the DB server processes structured query language (SQL) without knowing the associated HTTP, while the web server cannot identify the response associated with the attacker's SQL query. To detect these types of attacks, the malicious user is tracked using knowledge on interaction between HTTP request and SQL query. However, this is a practical challenge because system's source code analysis and its application logic needs to be understood completely. In this study, we proposed a scheme to find the HTTP request associated with a given SQL query using only system log files. We first generated an HTTP request-SQL query map from system log files alone. Subsequently, the HTTP request associated with a given SQL query was identified among a set of HTTP requests using this map. Computer simulations indicated that the proposed scheme finds the HTTP request associated with a given SQL query with 94% accuracy.