• Asian Pacific Journal of Cancer Prevention
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• v.16 no.9
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• pp.3645-3651
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• 2015

Background: Previous studies evaluating the association between the xeroderma pigmentosum group G (XPG) Asp1104His polymorphism and head and neck cancer susceptibility have proven controversial. This meta-analysis of the literature was performed to obtain a more precise estimation of the relationship. Materials and Methods: We systematically searched PubMed, Embase and Web of Science with a time limit of Dec 18, 2014. Odds ratios (ORs) with 95% confidence intervals (CIs) were used to assess the strength of any association. Results: We performed a meta-analysis of eight published case-control studies, including 3,621 cases and 5,475 controls. Overall, no significant association was found between the XPG Asp1104His polymorphism and head and neck cancer susceptibility under all genetic models. In the subgroup analysis by ethnicity, the XPG Asp1104His polymorphism had statistically significant association with elevated head and neck cancer risk under CC vs GG (OR=1.24, 95% CI=1.00~1.54) and the recessive model (OR=1.22, 95%CI=1.01~1.46) in Asian populations. A similar result was found under CC vs GG (OR =1.22, 95%CI=1.01~1.47) in the population based subgroup by source of control. When performed by tumor site, the XPG Asp1104His polymorphism had statistically significant association with elevated laryngeal cancer under all genetic models (CC vs GG: OR=1.59, 95% CI=1.16~2.19; GC vs GG: OR=1.38, 95%CI=1.10~1.72; dominant model: OR=1.42, 95% CI=1.15~1.74; recessive model: OR=1.36, 95% CI=1.02~1.81). Conclusions: This meta-analysis suggested that the XPG Asp1104His polymorphism is a risk factor for head and neck cancer susceptibility, especially for laryngeal cancer and in Asian populations.

• Journal of the Korea institute for structural maintenance and inspection
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• v.16 no.3
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• pp.60-66
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• 2012

This paper aims to constitute a feedback vibration control system using wireless sensor networks and experiment it on a model structure to verify its effectiveness. For the purpose, we set up a feedback vibration control system composed of a wireless input/output(I/O) sensor node based on bluetooth, a home-made shear type MR damper, a shaker which generates a constant size of sine wave, and a simple beam model structure. The vibration control experiment was performed by shaking the 1/4 point of beam with a shaker. At the moment of shaking, we controled the vibration with MR damper which was placed vertically on the center of beam. Simultaneously, by acquiring acceleration response at the 2/4 point of beam, we evaluated the effectiveness of control capability. The control command was set to send a voltage signal to MR damper when the acceleration response, acquired from the wireless I/O sensor node placed at the center of beam, was more than a certain amount. Although the realtime feedback vibration control system constituted in this paper is effective only within a limited command system, it has been proven that the system was able to effectively decrease the vibration of structure by generating a control command aimed for realtime purpose. The system also showed a possibility to be used as a structural response control system adapting a variety of semi-active control algorithm.

• Journal of the Korea Society for Simulation
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• v.28 no.2
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• pp.159-167
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• 2019

In the field of defense M&S, we are actively pursuing researches that interoperable multiple war game models to simulate various combat environments at the same time. Although the 'unit DB(Database)' for operating the war game models is originated from the identical data, it has been recognized that the method of expressing the attribute of the data is different and the cross reference is impossible. As a result, it makes unnecessary time and effort in establishing the same unit DB in the organizations that operate the war game model. In this study, a method of reusing the unit DB of the training war game model to the analysis war game model with similar resolution and simulated logic was applied to the actual field. For this purpose, we defined the procedure for converting the unit DB by analyzing metadata of the 'Chang-Jo21', a combat training model for corps and division, and the 'Vision21', an analysis model for corps and division operation plan. And we introduced an algorithm that can map different metadata of two unit DBs. This study was meaningful as the first attempt to map and integrate heterogeneous metadata semantically for the reuse of unit DB between different war game models in defense M&S field. Also, it provided implications for the necessity of paradigm shift that reuse of the unit DB between two different war game models is possible and the need for standardization of the unit DB metadata in the defense M&S filed.

• Convergence Security Journal
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• v.24 no.1
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• pp.51-57
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• 2024

Although industrial control systems (ICSs) recently keep evolving with the introduction of Industrial IoT converging information technology (IT) and operational technology (OT), it also leads to a variety of threats and vulnerabilities, which was not experienced in the past ICS with no connection to the external network. Since various control command messages are sent to field devices of the ICS for the purpose of monitoring and controlling the operational processes, it is required to guarantee the message integrity as well as control center authentication. In case of the conventional message integrity codes and signature schemes based on symmetric keys and public keys, respectively, they are not suitable considering the asymmetry between the control center and field devices. Especially, compromised node attacks can be mounted against the symmetric-key-based schemes. In this paper, we propose message authentication scheme based on double hash chains constructed from cryptographic hash function without introducing other primitives, and then propose extension scheme using Merkle tree for multiple uses of the double hash chains. It is shown that the proposed scheme is much more efficient in computational complexity than other conventional schemes.

• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.2051-2056
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• 2003

In this paper, a tele-manipulation in explosive ordnance disposal(EOD) applications is discussed. The ROBHAZ-DT2 is developed as a teleoperated mobile manipulator for EOD. In general, it has been thought that the robot must have appropriate functions and accuracy enough to handle the complicated and dangerous mission. However, the research on the ROBHAZ-DT2 revealed that the teleoperation causes more restrictions and difficulties in EOD mission. Thus to solve the problem, a novel user interface for the ROBHAZ-DT2 is developed, in which the operator can interact with various human senses (i.e. visual, auditory and haptic sense). It enables an operator to control the ROBHAZ-DT2 simply and intuitively. A tele-manipulation control scheme for the ROBHAZ-DT2 is also proposed including compliance control via force feedback. It makes the robot adapt itself to circumstances, while the robot faithfully follows a command of the operator. This paper deals with a detailed description on the user interface and the tele-manipulation control for the ROBHAZ-DT2. An EOD demonstration is conducted to verify the validity of the proposed interface and the control scheme.

• Journal of Biomedical Engineering Research
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• v.36 no.6
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• pp.264-270
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• 2015

A mock circulatory loop system has been developed to construct a simulator for trainees in cardiopulmonary bypass systems or to simulate a test environment for cardiac-assist devices. This paper proposes a computerized mock circulatory loop system whose node is modularized by using a servo control flow regulator to simulate dynamic change of the hemodynamic status. To observe the effect of time-varying resistance, one with hemodynamic properties, the proposed system replicates the planned cross-sectional areas of the outlet of a ventricular assist device in terms of voltage input of a servo valve. The experiment is performed (1) for steady-input commands of selected area sizes and (2) for dynamic commands such as monotonous increase and decrease, and oscillatory functions of the voltage input, and a computer program based on LabVIEW (National Instruments, Austin, USA) processes every measured data and control command to the servo valve. The results show that the pressure and flow at the target points with respect to time-varying resistance match intuitive estimation: the pressure at the outlet and the pressure drop between both sides of the valve increased and the flow at the outlet decreased for increased resistance.

• Proceedings of the KIPE Conference
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• 1998.10a
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• pp.325-329
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• 1998

This paper describes the controller for the improving speed control of the AC servo motor. The microprocessor provides an output to the difference in command. the servo system improves the characteristics of speed control. When the motor is running at the same speed as set by the reference signal, the speed encoder also provides a signal of the same frequency. Thus, the microprocessor controlled digital techniques enable to realize the flexible performance and control which was possible with time constant of linear acceleration/deceleration. We can know that optimal speed of machining center is 75msec in 30000mm/min and actually, 75msec is using on machining center. Finally experimental results prove excellent performance of this control system. This can be reduced error with more exact measure of actual speed. The system can be adaptable to CNC machine.

• Proceedings of the KIPE Conference
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• 1998.07a
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• pp.347-351
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• 1998

This paper describes the controller for the improving speed control the AC servo motor. The microprocessor provides an output to the difference in command. The servo system improves the characteristics of speed control. When the motor is running at the same speed as set by the reference signal, the speed encoder also provides a signal of the same frequency. Thus, the microprocessor controlled digital techniques enable to realize the flexible performance and control which was possible with time constant. We can know that optimal speed of machining center is 75msec in 30000mm/min and actually, 75msec is using on machining center. Finally experimental results prove excellent performance of this control system. This can be reduced error with more exact measure of actual speed. The system can be adaptable to CNC machine.

• Journal of the Korean Society of Systems Engineering
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• v.2 no.1
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• pp.54-60
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• 2006

LCC(Launch Control Center) in NARO space center performs a data monitoring and control through the interface to the external system of launch vehicle. Launch control function needs high reliability and processing speed. Hence, LCS(Launch Control System) is made up a real time system. An important role of the LCS Prototype is discovering a risk element and minimizing it through developing a launch control system. This paper deals with a real time data processing among the simulator, gateway, data distribution server, command and control server which is involving LCS Prototype.

• Journal of the Korea Institute of Military Science and Technology
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• v.18 no.4
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• pp.451-458
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• 2015

This paper handles self-collision avoidance for a rescue robot with redundant manipulators. In order to detect all available self-collisions in advance, minimum distances between arbitrary robot parts should be monitored in real-time. For the minimum distance estimation, we suggest a modified method from a previous skeleton algorithm which has less computation burden and realize collision avoidance based on a potential function using the proposed algorithm. The resultant command by collision avoidance should not disturb a given primary task, so null-space of joint solution from a CLIK is utilized for collision avoidance by a gradient projection method.