• Journal of Institute of Control, Robotics and Systems
• /
• v.22 no.7
• /
• pp.530-535
• /
• 2016

In this paper, the TTSE (Target size and Triangulation-based target Size Estimator) algorithm is proposed to estimate static target size in an imaging environment. The target size information is an important factor for accurate imaging target tracking. However, the imaging sensor cannot generate distance between the missile and target to calculate the target size. To overcome the problem, we propose the TTSE algorithm, which is based on target size and triangulation. The proposed method performance is tested in a target intercept scenario. The experiment results show that the proposed algorithm has better performance than the conventional algorithm (ET-TSE) for accurate CCD target size estimation.

• Journal of Institute of Control, Robotics and Systems
• /
• v.20 no.1
• /
• pp.29-36
• /
• 2014

In this paper, a novel MBE (Model Based target size Estimator) is presented for SDIIR (Strap Down Imaging Infrared) seekers. The target tracking requires the target size information for which residual range between target and missile should be provided. Unfortunately, in general, the missile with passive sensor such as IIR (Imaging Infrared), CCD (Coupled Charging Device) cannot obtain range information. To overcome the problem, the proposed method enables the SDIIR seeker to estimates target size by using target size model and track the target. The performance of proposed method is tested at IIR target tracking of target intercept scenario. The experiment results show that the proposed algorithm has the relatively good performance.

• Journal of Communications and Networks
• /
• v.17 no.3
• /
• pp.241-246
• /
• 2015

In this paper, we consider a relaying system which employs a single relay in a wireless network with distributed sources and destinations. Here, all source, destination, and relay nodes are equipped with multiple antennas. For amplify-and-forward relay systems, we confirm the achievable sum rate through a joint multiple source precoders and a single relay filter design. To this end, we propose a new linear processing scheme in terms of maximizing the sum rate performance by applying a blockwise relaying method combined with geometric programming techniques. By allowing the global channel knowledge at the source nodes, we show that this joint design problem is formulated as a standard geometric program, which can guarantees a global optimal value under the modified sum rate criterion. Simulation results show that the proposed blockwise relaying scheme with the joint power allocation method provides substantial sum rate gain compared to the conventional schemes.

• Journal of the Korean Institute of Navigation
• /
• v.20 no.4
• /
• pp.45-58
• /
• 1996

$\ulcorner$Ministry Of Maritime Affairs And Fisheries$\lrcorner$was established on 8 August 1996 by emerging ex-$\ulcorner$Maritime and Port Administration$\lrcorner$, $\ulcorner$Fisheries Administration$\lrcorner$and some other marine-related organs such as $\ulcorner$Maritime Police Agency$\lrcorner$, $\ulcorner$Marine Accident Inquiry Agency$\lrcorner$, etc., for the purpose of enhancing development of national marine polices in various aspect and promoting marine safety and environmental protection activities. Therefore, the unification of marine casualty statistics is required for the need of appreciating present condition and problem. This paper shows the Client/Server computing system which could replace the existing Main Frame system set up by Maritime and Port Administration and Marine Accident Inquiry Agency. It also gives the way to connect every casualty related organ for data exchange of casualty information and INTERNET for opening casualty information to the public. So, applicable techniques and basic policy direction is dealt with.

• Korean Journal of Remote Sensing
• /
• v.22 no.3
• /
• pp.229-234
• /
• 2006

In tactical theater, it is crucial to detect ground moving targets and to locate them precisely. This problem can be resolved by using SAR (Synthetic Aperture Radar) sensors providing GMTI (Ground Moving Target Indication) capability. In general, to implement a robust GMTI sensor is not simple because of the strong competitions between target signals and clutter signals from the ground, and low speed of moving targets. Contrary to the case that a delay canceller is mostly suitable for ground surveillance radars, DPCA (Displaced Phase Centered Antenna) or STAP (Space Time Adaptive Processing) techniques have been widely adapted for GMTI function of modern airborne radars. In this paper, a new scheme of DPCA using two passive antennas with vertical separation is proposed, which also provides good clutter cancellation performance. The proposed scheme realizes full azimuth coverage for DPCA operation on an airborne platform, which is impossible with classical DPCA configuration. Simulations using various conditions have been performed to validate the proposed scheme, and the results are acceptable.

• Journal of Korea Multimedia Society
• /
• v.22 no.8
• /
• pp.887-896
• /
• 2019

In this paper, we discuss an optimization approach for time-synchronizations in networked simulators. This method is a sub-technology that is required to combine heterogeneous simulators into a single simulation. In previous time-synchronization studies, they had built a network system among networked simulators. The network system collects network packets and adds time-stamps to the networked packets based on the time that occurs in events of simulation objects in the individual simulators. Then, it sorts them in chronological order. Finally, the network system applies time-synchronization to each simulator participating in interworking sequentially. However, the previous approaches have a limitation in that other participating simulators should wait for while processing an event in a simulator in a time stamp order. In this paper, we attempt to solve the problem by optimizing time-synchronizations in networked simulation environments. In order to prove the practicality of our approach, we have conducted an experiment. Finally, we discuss the contributions of this paper.

• International Journal of Advanced Culture Technology
• /
• v.1 no.2
• /
• pp.18-23
• /
• 2013

In this paper, we consider the problem of designing optimal sensing time and the minimization of energy consumption in the Cognitive radio Network. Trade-off between throughput and the sensing time are observed, and the equations are derived for the optimal choice of design variables. In this paper, we also look at the optimization problem involving all the design parameters together. The advantages of the proposed scheme for the spectrum sensing and access process are shown through simulation.

• 제어로봇시스템학회:학술대회논문집
• /
• 2005.06a
• /
• pp.1060-1065
• /
• 2005

An Independent Administrative Corporation Japan Agency for Marine-Earth Science and Technology (JAMSTEC) is developing light-and-small Autonomous Underwater Vehicles (AUV)$^{1)}$, named 'MR-X1' (Marine Robot Experimental 1), which can cruise, investigate and observe by itself without human's help. In this paper, we consider the motion control problem of 'MR-X1' and derive a controller. Since the dynamic property of 'MR-X1' is changed by the influence of the speed, the mathematical model of 'MR-X1' becomes the nonlinear model. In order to design a controller for 'MR-X1', we generally apply nonlinear control theories or linear control theories with some constant speed situation. If we design a controller by applying Linear Quadratic (LQ) optimal control theory, the obtained controller only compensates t e optimality at the designed speed situation, and does not compensate the stability at another speed situations. This paper proposes a controller design method using Linear Matrix Inequalities (LMIs)$^{2),3),4)}$, which can adapt the speed variation of 'MR-X1'. And examples of numerical analysis using our designed controller are shown.

• Journal of Korean Society for Quality Management
• /
• v.40 no.3
• /
• pp.245-258
• /
• 2012

Purpose: Recently, many quality issues are aroused in military forces, such as failures in K-series weapons, combat boots defects and 40mm ammunition explosion accident. To address these problems, the one and only government defense quality assurance agency, DTaQ(Defense Agency for Technology & Quality) tried to improve many quality assurance procedures and introduced new systems such as MRA(Manufacturing Readiness Assessment), TRA(Technology Readiness Assessment), and etc. However, as the amount of war supplies increasing every year, the resource(budget and manpower) for quality assurance is limited. Therefore, DTaQ had difficulty to handle the issue efficiently and effectively, and we propose the method to address this problem. Methods: The most popular quality assurance technique is a sampling method, in this research, we first review the many sampling techniques and compare the strength and weakness of each method. After then, we selected the most appropriate sampling techniques and applied the procedures in combat force support material and ammunition areas. Results: We can reduce the number of samples dramatically, thus the required amount of labor time and money can be saved. Also, the new sampling technique enforces the supplier to produce the product which meets the target value(desirable value). Conclusion: We can reduce the number of samples dramatically, thus the required amount of labor time and money can be saved. Also, the new sampling technique enforces the supplier to produce the product which meets the target value(desirable value). Lastly, since the new sampling method requires many numerical calculations, we developed a simple android OS smart-phone application which can be used easily in field.

• Asia-Pacific Journal of Business
• /
• v.11 no.4
• /
• pp.205-224
• /
• 2020

Purpose - This study aimed to identify the effects of ownership structures on agency costs in internationally diversified firms listed on the KOSDAQ market. Design/methodology/approach - A total of 5,824 samples were finally selected and empirically analyzed for a total of nine years from 2011 to 2019, during which the International Accounting Standards had been mandatory for firms listed on the KOSDAQ market. Findings - The results of this study showed that the effects of ownership structures on the ratio of asset turnover are positive for the major share and foreign equity ratios of international diversified firms. Moreover, by selecting the ratio of entertainment expenses as a proxy for agency expenses, this study confirmed that the effects of the ownership structure of an international diversified entity on entertainment expenditure were determined to show a significantly negative relation to entertainment expenditure, thus indicating that the higher the ratio of major shareholders, the more appropriately control the expenditure of entertainment expenses through arbitrary private deviations of the management.Furthermore, considering the effect of the ownership structure on the expenditure of sales and administrative expenses as a proxy variable for agency costs, this study verified that the majority share ratio of international diversified firms was negative to the expenditure of sales and administrative expenses, confirming that the higher the share of major shareholders, the lower the selling and administrative costs, but insignificant.Finally, as a result of determining whether the ownership structure of an international diversified firm affects the holding of free cash, the majority share of this firm shows a significantly negative relation to the ratio of the holding of surplus cash, indicating that the higher the proportion of major shareholders, the more appropriately control the holding of the entity's free cash through arbitrary private deviance by the manager. Research implications or Originality - Major shareholders of an internationally diversified firm listed on the KOSDAQ market play a positive role in the firm's performance by properly controlling agency costs that may be incurred by the management.