• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.8 no.6
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• pp.89-95
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• 2008

The introduction of wireless information technology gives rise to new mobile services in all kinds of areas of out daily life. Mobile healthcare system is a production of composite ICT (Information and Communication Technology) which focused on signal sensing, processing, and communication in wireless environment. The mobile and wireless revolution promises not only expanded access to patient health information, but also improved patient care. In this paper, we describe a surrogate host based mobile healthcare information system which utilized Grid computing for real-time ECG signal processing. The surrogate host provides seamless interface between mobile device and Medical Grid portal. The security extension of GSI (Grid Security Infrastructure) allows mobile users to access Grid portal in a secure and convenient manner. The presented system architecture can be used as a secure enterprise mobile healthcare system for hospital physicians.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.22 no.2
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• pp.375-381
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• 2018

As smart home network services such as home CCTV, outdoor control of home appliances, home security and disaster prevention services become popular, there appear various affiliated products including smart home gateway and smart speaker. Since those services are generally developed on the vendors' individual hardware and software platforms, it is not much expected for them to interwork well among different architecture and communication methods. In this paper, we propose a new home network service system running on an open source platform to address such issues. We implemented a home network system using OpenWRT-based wireless router(or access point) and Zigbee communication technology. In the proposed system, a wireless router replaces a commercial home gateway and small control units implemented with Arduino control electronic devices and sensors in home. Several service scenarios are also implemented to verify the operability of the proposed system.

• Journal of the Korea Society of Computer and Information
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• v.18 no.4
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• pp.87-96
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• 2013

In this paper, we suggest redesigned RTP protocol that is able to perform encryption of VoIP media information for single private network and between the different private networks. And we conduct a test for performance analysis. Such as SRTP or ZRTP methods have been used for VoIP media encryption. But, the existing encryption techniques have problem that can not perform end-to-end encryption between different private networks. In order to solve this problem, in this paper, we redesign RTP protocol. Redesigned RTP includes all information for encryption of VoIP media. Therefore the encryption is not affected by modification of SIP and SDP information that occurred in gateway. Also, redesigned RTP includes code for whether or not to apply encryption. By using the code, modification of RTP header from gateway prevents. As a result, redesigned RTP maintain the integrity and the RTP is able to perform encryption between the different private networks. Also, we conduct a test for performance analysis of SRTP, ZRTP and redesigned RTP.

• Journal of the Korean Institute of Telematics and Electronics
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• v.26 no.5
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• pp.117-126
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• 1989

In this paper, a new placement algorithm for gate array lay out design is proposed. The proposed algorithm can treat the variable-sized macrocells and by considering the I/Q pad locations, the routing between I/Q pads and the internal region of a chip can be automated effectively. The algorithm is composed of 3 parts. which are initial partitioning, initial placement and placement improvement. In the initial placement phase, a given circuit is partitioned into 5 sub-circuits, by clustering method with considers connectivities of cells not only with I/Q pads but also with related partitioned groups is used repeatedly to assign a unique position to each cell. In the placement improvement phase, the concept of probabilistic wiring density is introduced, and cell moving algorithm is proposed to make the density in a chip even.

• Journal of Internet Computing and Services
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• v.8 no.3
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• pp.85-98
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• 2007

In distributed computing paradigm, mobile surrogate systems have not gained wide acceptance because of security concerns that have not been suitably addressed yet. Currently even the widely used Grid middleware, Globus, does not have a host authentication mechanism, which makes it hard to provide high performance Grid computing capabilities to mobile clients. In this paper, a mobile Grid service framework is designed and implemented in order to provide Grid services to mobile host such as PDA. The surrogate host-based system allows mobile hosts to be provided with Grid services while moving. The implemented mobile Grid services system has been applied to mobile healthcare system which utilizes Grid computing for ECG signal processing. The presented system framework can be used as a secure enterprise mobile healthcare system for hospital physicians.

• The KIPS Transactions:PartA
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• v.17A no.1
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• pp.27-32
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• 2010

Logical Effort is a simple hand-calculated method that measures quick delay estimation. It has the advantage of reducing the design cycle time. However, it has shortcomings in designing a path for minimum area or power under a fixed-delay constraint. In this paper, we propose an equal delay model and, based on this, a method of optimizing power-delay efficiency in a logical path. We simulate three designs of an eight-input AND gate using our technique. Our results show about 40% greater efficiency in power dissipation than those of Logical Effort method.

• Proceedings of the Korea Information Processing Society Conference
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• 2020.11a
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• pp.721-724
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• 2020

멀티 클라우드는 다양한 클라우드 제공자들의 클라우드 서비스를 연동하여 사용자에게 제공하는 기술로 최근 4차 산업혁명 기술의 발전에 따라 대용량 데이터의 수용, 대용량 계산 등을 단일 클라우드에서 활용하기 어려워 데이터를 가까운 클라우드 자원을 활용하여 분석하거나 서비스를 가까운 지역에서 제공하기 위해 등장한 기술이다. 그러나 멀티 클라우드 제공처마다 동일한 기능을 서로 다른 인터페이스와 파라미터를 사용해야 하며, 시스템의 버전 증가에 따른 인터페이스 변화 시 멀티 클라우드 연동을 다시 해주어야 하는 번거로움이 있다. 본 논문에서는 멀티 클라우드마다 다른 인터페이스를 분석하고 공통 요소를 도출 및 규격화하여 연동을 위한 게이트웨이를 제안한다. 인터페이스 제공을 위해 필수적인 요소와 부가적인 요소를 정리하여 공통 규격으로 만들어 멀티 클라우드 시스템 구성 및 서비스 이용에 편의성을 향상시킬 수 있다. 또한, 멀티 클라우드 인터페이스를 마이크로 서비스로 구성하여 새로운 클라우드 서비스 등록과 기존 등록된 서비스의 인터페이스 버전 변화에도 대응 가능할 수 있도록 설계하여 손쉽게 연동 서비스를 이용할 수 있는 시스템을 제안한다.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.32 no.6A
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• pp.337-345
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• 2012

A model test is performed to investigate the dynamic behavior of truss type lift gate which is being constructed by the four major rivers project. The gate dimensioned 40 m in width, 9m in height is scaled with the ratio of 1:25 and is made of acryl panel and supplemented weight by lead in the concrete test flume dimensioned 1.2 m in width, 0.5 m in height and 30m in length. Firstly natural frequencies of the model gate are measured and compared with the numerical results for the calibration. The amplitudes of the vibration are measured under the different gate opening, upstream water level conditions. Also models with bottom angle $20^{\circ}$, $35^{\circ}$ and $50^{\circ}$ are tested and compared to find out a proper shape of bottom structure which minimizes the gate vibration. These test results presents a basic data for the guide manuals of gate management and a design method to reduce the gate vibration of truss type lift gate.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.5
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• pp.2313-2318
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• 2012

With the widely applications of tactical radio networks, end-to-end secure speech communication in the heterogeneous network has become a very significant security issue. High-grade end-to-end speech security can be achieved using encryption algorithms at user ends. However, the use of encryption techniques results in a problem that encrypted speech data cannot be directly transmitted over heterogeneous tactical networks. That is, the decryption and re-encryption process must be fulfilled at the gateway between two different networks. In this paper, in order to solve this problem and to achieve optimal end-to-end speech security for heterogeneous tactical environments, we propose a novel mechanism for end-to-end secure speech transmission over ultra high frequency (UHF) and public switched telephone network (PSTN) and evaluate against the performance of conventional mechanism. Our proposed mechanism has advantages of no decryption and re-encryption at the gateway, no processing delay at the gateway, and good inter-operability over UHF and PSTN.

• Journal of Digital Convergence
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• v.17 no.12
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• pp.235-241
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• 2019

The structure of the IoT can be divided into devices, gateways, and servers. First, the gateway collects data from the device, and the gateway sends data to the server through HTTP protocol, Websocket protocol, and MQTT protocol. The processing server then processes, analyzes, and transforms the data, and the database makes it easy to store and use this data. These IoT services are basically centralized structures with servers, so attacks on the entire platform are concentrated only on the central server, which makes hacking more successful than distributed structures. One way to solve this problem is to develop IoT that combines blockchain. Therefore, the proposed research suggests that the blockchain is a distributed structure, in which blocks containing small data are connected in a chain form, so that each node agrees and verifies the data with each other, thereby increasing reliability and lowering the probability of data forgery.