• KSII Transactions on Internet and Information Systems (TIIS)
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• v.5 no.11
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• pp.1929-1945
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• 2011

RFID technologies have attracted a lot of attention in recent years because of their cost/time-effectiveness in large-scale logistics, supply chain management (SCM) and other various potential applications. One of the most important issues of the RFID-based systems is how quickly tags can be identified. Tag collision arbitration plays a more critical role in determining the system performance especially for passive tag-based ones where tag collisions are dealt with rather than prevented. We present a novel tag collision arbitration protocol called Optimum Frame-Slotted Aloha (OFSA). The protocol has been designed to achieve time-optimal efficiency in tag identification through an analytic study of tag identification delay and tag number estimation. Results from our analysis and extensive simulations demonstrate that OFSA outperforms other collision arbitration protocols. Also, unlike most prior anti-collision protocols, it does not require any modification to the current standards and architectures facilitating the rollout of RFID systems.

• Journal of information and communication convergence engineering
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• v.10 no.4
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• pp.337-342
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• 2012

The medical industries are integrated with information technology with mobile devices and wireless communication. The advent of mobile healthcare systems can benefit patients and hospitals, by not only providing better quality of patient care, but also by reducing administrative and medical costs for both patients and hospitals. Security issues present an interesting research topic in wireless and pervasive healthcare networks. As information technology is developed, many organizations such as government agencies, public institutions, and corporations have employed an information system to enhance the efficiency of their work processes. For the past few years, healthcare organizations throughout the world have been adopting health information systems (HIS) based on the wireless network infrastructure. As a part of the wireless network, a mobile agent has been employed at a large scale in hospitals due to its outstanding mobility. Several vulnerabilities and security requirements related to mobile devices should be considered in implementing mobile services in the hospital environment. Secure authentication and protocols with a mobile agent for applying ubiquitous sensor networks in a healthcare system environment is proposed and analyzed in this paper.

• ETRI Journal
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• v.34 no.1
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• pp.55-65
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• 2012

E-voting is expected to offer prominent advantages over traditional voting methods. Advantages include faster tallying, greater accuracy, prevention of void ballots, and lower cost. However, many experts express concerns about the potential for large-scale fraud. Recently, many paper based end-to-end (E2E) voter verifiable systems providing individual verifiability and universal verifiability have been proposed. These systems, unlike previous voting systems, are used in polling booths and without access to trusted computing devices at the time of voting. In this paper, we propose a practical and secure E2E voter verifiable system using a paper receipt based on cryptographic technologies.

• Journal of Institute of Control, Robotics and Systems
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• v.5 no.5
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• pp.600-613
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• 1999

This paper focuses on development of a performance manager for IEEE 802.4 token bus networks to serve large-scale integrated systems. In order to construct the management algorithm, the principles of fuzzy logic, genetic algorithm, and neural network have been combined to represent human knowledge and to imitate of human inference mechanism. Through the simulation experiments, it is shown that the proposed performance manager is capable of improving the network performance without a priori knowledge.

• Journal of Institute of Control, Robotics and Systems
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• v.18 no.5
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• pp.413-418
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• 2012

This paper presents a multi-robot path planner for environment exploration and monitoring. Robotics systems are being widely used as data measurement tools, especially in dangerous environment. For large scale environment monitoring, multiple robots are required in order to save time. The path planner should not only consider the collision avoidance but efficient coordination of robots for optimal measurements. Nonlinear spring force based planning algorithm is integrated with the spatial gradient following path planner. Perturbation/Correlation based estimation of spatial gradient is applied. An algorithm of tuning the stiffness for robot coordination is presented. The performance of the proposed algorithm is discussed with simulation results.

• Journal of Institute of Control, Robotics and Systems
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• v.20 no.4
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• pp.463-467
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• 2014

High precision machining technology has become one of the most important parts in the development of a precision machine. Such a machine requires high precision positioning as well as high speed on a large workspace. For machining systems having high precision positioning with a long stroke, it is necessary to examine the repeatability of the reference position decision. Though ball-screw driven linear stages equipped with linear scale have high precision feed drivers and a long stroke, they have some limitations for reference position decisions if they have not been equipped with an accurate home sensor. This study is performed to experimentally examine the repeatability for home position decision of a photo micro sensor as a home switch of a ball-screw driven linear stage by using a capacitance probe.

• Journal of Korea Multimedia Society
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• v.17 no.12
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• pp.1494-1502
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• 2014

Since smartphones are utilized in the ranges from personal usages to governmental data exchanges, known but not patched vulnerabilities in smartphone operating systems are considered as major threats to the public. To minimize potential security breaches on smartphones, it is necessary to estimate possible security threats. So far, there have been numerous studies conducted to evaluate the security risks caused by mobile devices qualitatively, but there are few quantitative manners. For a large scale risk evaluation, a qualitative assessment is a never ending task. In this paper, we try to calculate relative risk levels triggered by software vulnerabilities from unsecured smartphone operating systems (Android and iOS) among 51 Asian countries. The proposed method combines widely accepted risk representation in both theory and industrial fields. When policy makers need to make a strategic decision on mobile security related agendas, they might find the presented approach useful.

• Proceedings of the Korea Society for Industrial Systems Conference
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• 2008.10b
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• pp.515-529
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• 2008

This study is a measurement of effectiveness to a job process for the hospital information system (HIS) used in the hospital industry. Using the effectiveness scale that I developed in the questionnaire of the ISO9241-11 quality model, I measured the importance level of HIS and its significance on a job practices in the large general hospitals within the country. The questionnaire showed that the importance level of domestic HISs was highest in the system used by staffs(mean=3) and to reduce a job process and increase the efficiency of work.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.50 no.11
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• pp.505-513
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• 2001

This paper presents the new three-level optimal control scheme for the large scale nonlinear systems, which is based on fast walsh transform. It is well known that optimization for nonlinear systems leads to the resolution of a nonlinear two point boundary value problem which always requires a numerical iterative technique for their solution. However, Three-level costate coordination can avoid two point boundary condition in subsystem. But this method also has the defect that must solve high order differential equation in intermediate level. The proposed method makes use of fast walsh transform, therefore, is simple in computation because of solving algebra equation instead of differential equation.

• Journal of Aerospace System Engineering
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• v.8 no.2
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• pp.49-54
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• 2014

The main purpose of Korea Space Launch Vehicle II(KSLV-II) Program is to develop a domestic launch vehicle that can deliver a 1.5ton class application satellite into a Low Earth Orbit(600~800km). The data management is an essential factor in systems engineering for success of large-scale complex systems development, and it systematically manages the information and technical data for the total life-cycle of a system. In this paper, data management policies and processes on KSLV-II program are presented, and product life-cycle management system for KSLV-II program is also presented.