• Journal of the military operations research society of Korea
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• v.31 no.2
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• pp.86-104
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• 2005

During the 'Cold War', DoD had focused on the high performance and timely acquisition which enabled quick field out the superior weapons than the enemy regardless of acquisition cost. But, after the cold war, the focus has been changed to the 'cost effective acquisition' of weapon systems because of tremendous investment cost & economic theory. The U.S. DoD has been tried to make 'the most effective acquisition system'(AR, Acquisition Reform) from mid-80's with their enough experienced program data, and as a result, they had launched the new acquisition procedure - DoD 5000 series - in 1996. DoD is continuously doing the study and making several improvements on the procedure after it had been once announced. On Oct 30. 2002, DoD noticed that they cancelled the DoD 5000 series documents(5000.1, 5000.2, 5000.2-R) and 5000.2-R will be reissued as a guide. The most recent version which focused on 1) evolutionary acquisition and spiral development, 2) procedure for future technology systems including software and IT, 3) supplement on the area of efficiency, flexibility, creativity and innovation of old system was issued by May 12. 2003. This article suggests a 'good idea' based on the reviewing of these DoD efforts for our defense acquisition regulation and procedure to go. It includes the CAIV concept application, IPT utilization, T&E method, cost or price based contract etc-all for the effective acquisition.

• Journal of Korean Institute of Industrial Engineers
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• v.39 no.4
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• pp.290-297
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• 2013

The increasing level of operation in high-tech industry is likely to require ever more complex structure in reliability problem. Furthermore, system failures are more significant on society as a whole than ever before. Reliability redundancy optimization problem (RROP) plays a important role in the designing and analyzing the complex system. RROP involves selection of components with multiple choices and redundancy levels for maximizing system reliability with constraints such as cost, weight, etc. Meanwhile, previous works on RROP dealt with system with perfect failure detection, which gave at most a good solution. However, we studied RROP with imperfect failure detection and switching. Using absorbing Markov Chain, we present not a good solution but the optimal one. In this study, the optimal system configuration is designed with warm and cold-standby redundancy for k-out-of-n system in terms of MTTF that is one of the performance measures of reliability.

• Journal of Sensor Science and Technology
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• v.18 no.5
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• pp.359-364
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• 2009

This paper presents flexible electrocardiography(ECG) sensors using micro electro mechanical systems(MEMS) and flexible printed circuit(FPC) technology. By using FPC technology, ECG sensors which consisted of an outer hook-shaped electrode and an inner circular-shaped electrode were fabricated on the polyimide substrate. Thereafter, the bipolar ECG sensor was miniaturized using MEMS technology. The ECG measurement capability was examined by attaching the sensor to the human chest and wrist. Performance of the proposed sensors was then compared with ECG measured by commercial Ag/AgCl electrodes. It was verified that ECG could be measured using proposed sensors at only single body.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.66 no.1
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• pp.55-60
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• 2017

Capacitor Charging Power Supply(CCPS) is one of the most important components of a pulsed power system. The CCPS is widely used in source of lasers, accelerators and plasma generators. This paper presents design of a dead time control circuit and operation characteristics for stable high repetition rate of high voltage CCPS. The CCPS consists of battery, high voltage transformer and controller with a dead time control circuit. A dead time control circuit was simulated by PSpice. The performance test of the CCPS was carried out with a 7[nF] load capacitor at output voltage of 50[kV] and a pulse repetition frequency of 100[Hz]. As a result, we can verify that charging and discharging waveform is stable at 100[Hz]. The experiment results indicate that 3[ms] dead time made it possible for stable high repetition rate of 100[Hz]. This paper paves the way for designing an advanced CCPS which is more applicable outside experiments.

• Journal of the Korea Institute of Military Science and Technology
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• v.14 no.6
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• pp.1097-1106
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• 2011

Tactical Information Communication Network(TICN), a concept-type integrated Military Communication system that enables precise command control and decision making, is designed to advance into high speed, large capacity, long distance wireless relay transmission. To support mobility in battlefield environments, the application of Ad-hoc networking technology to its wireless communication has been examined. Ad-hoc network works properly only if the participating nodes cooperate in routing and packet forwarding. However, if selfish nodes not forwarding packets of other nodes and malicious nodes making the false accusation are in the network, it is faced to many threats. Therefore, detection and management of these misbehaving nodes is necessary to make confident in Ad-hoc networks. To solve this problem, we propose an efficient intrusion detection technique to detect and manage those two types of attacks. The simulation-based performance analysis shows that our approach is highly effective and can reliably detect a multitude of misbehaving node.

• Journal of the Korea Institute of Military Science and Technology
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• v.17 no.1
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• pp.25-32
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• 2014

Recently supercavitating torpedo has been studied because of its high-speed performance as the next generation of underwater weapon systems. In this study, we present a numerical method based on the potential flow. Characteristic features of the shape of supercavities and drag forces are investigated. In addition, we introduce a viscous-potential method to compensate for the effects of viscosity. The results are compared with viscous calculations using a commercial package, FLUENT V13.

• Journal of the Optical Society of Korea
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• v.8 no.4
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• pp.174-181
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• 2004

Various kinds of systems, that can do target recognition and position detection simultaneously by using infrared sensing detectors, have been developed. In this paper, the detection system TRSS (Thermal target Recognition by Spiral Scanning) adopts linear array shaped uncooled IR detector and uses spiral type fast scanning method for relative position detection of target objects, which radiate an IR region wavelength spectrum. It can detect thermal energy radiating from a 9 m-size target object as far as 200 m distance. And the maximum field of a detector is fully filled with the same size of target object at the minimum approaching distance 50 m. We investigate two types of lens systems. One is a singlet lens and the other is a doublet lens system. Every system includes one aspheric surface and free positioned aperture stop. Many designs of F/1.5 system with ${\pm}5.2^{\circ}$ field at the Efl=20, 30 mm conditions for single element and double elements lens system respectively are compared in their resolution performance [MTF] according to the aspheric surface and stop position changing on their optimization process. Optimum design is established including mechanical boundary conditions and manufacturing considerations.

• Journal of Internet Computing and Services
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• v.14 no.2
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• pp.45-51
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• 2013

In this paper, the combination of ultraviolet and infrared sensors based design for flame signal detection algorithms was proposed with the application of light-wavelength from burning. And, the performance result of image detection was compared by an ultraviolet sensor, an infrared sensor, and the proposed dual-mode sensors(combination of ultraviolet and infrared sensors).

• Journal of Korean Society for Quality Management
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• v.47 no.3
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• pp.425-435
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• 2019

Purpose: The purpose of this study was to resolve the Naval ship's Local Operation Panel(LOP) malfunction problems which caused by overheating in summer season and dispatching to equatorial regions. Methods: Instead of using dual type heat insulation materials(consist with ceramic wool and glass wool), aerogel heat insulation materials were used for decreasing heat emissions from gas-turbine heat waste steam pipes passing water-jet- room. Experiment and Computational analysis of heat flow were conducted to analyze the internal room temperature changes. Results: The results of this study are as follows; The aerogel heat insulation materials suppress heat emission more efficiently than dual type insulation materials. The cold surface temperature of insulation was far more decreased and internal room, LOP surface temperature also showed significant results too. Conclusion: The substituted heat insulation materials appeared remarkable performance in decreasing room temperature that it could be used for suppressing the LOP overheatings and malfunctions.

• Journal of Aerospace System Engineering
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• v.13 no.5
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• pp.16-23
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• 2019

This paper describes the design and analysis of a periscope imaging system installed at the engine test facility in the Agency for Defense Development. The periscope system is a cylinder-shaped image observation system installed at the rear of the engine and at the top of the diffuser. The periscope system has high risk of breaking because it is directly affected by high temperature (2300 K) and products of combustion. Thus, we used 1D heat transfer calculation, and 2D and 3D CFD analysis to confirm the heat flux and temperature distribution. Also, the cooling performance was verified. In the current design, using the periscope system, we can see flame shapes, control of the nozzle, and stability of the exhaust flow visually.