• Journal of the Korea Institute of Military Science and Technology
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• v.13 no.4
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• pp.673-682
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• 2010

This paper describes and analyzes a various generation methods of the mutually orthogonal polyphase sequences with low cross-correlation peak sidelobe and low autocorrelation peak sidelobe levels. The mutual orthogonality is the key requirement of multi-static or MIMO(Multi-Input Multi-Output) radar systems which provides the good target detection and tracking performance. The polyphase sequences, which are generated by SA(Simulated Annealing) and GA(Genetic Algorithm), have been analyzed with ACF(Autocorrelation Function) PSL(Peak Sidelobe Level) and CCF(Crosscorrelation Function) level at the matched filter output. Also, the ambiguity function has been introduced and simulated for comparing Doppler properties of each sequence. We have suggested the phase selection rule for applying multi-static or MIMO systems.

• Journal of Information Processing Systems
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• v.14 no.6
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• pp.1307-1317
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• 2018

To deal with the problems of occlusion, pose variations and illumination changes in the object tracking system, a regression model weighted multi-templates mean-shift (MS) algorithm is proposed in this paper. Target templates and occlusion templates are extracted to compose a multi-templates set. Then, the MS algorithm is applied to the multi-templates set for obtaining the candidate areas. Moreover, a regression model is trained to estimate the Bhattacharyya coefficients between the templates and candidate areas. Finally, the geometric center of the tracked areas is considered as the object's position. The proposed algorithm is evaluated on several classical videos. The experimental results show that the regression model weighted multi-templates MS algorithm can track an object accurately in terms of occlusion, illumination changes and pose variations.

• Transactions of Materials Processing
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• v.31 no.2
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• pp.96-102
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• 2022

The multi-point dieless forming technology is one of flexible forming technologies that can form 3D curved surfaces of various shapes utilizing a lot of punch arrangements. A new technology that can simultaneously apply high-temperature forming and flexible forming technology by fusing local heating effect to such multi-point dieless forming technology was proposed in the present study. A simple local heating multi-point dieless forming apparatus was fabricated to confirm the applicability of this new technology. This equipment was designed to be used as a heat source by inserting heating cartridges in the head of the multi-point punch. Cartridges were used for all individual punches. Using the manufactured equipment, the time to raise the temperature to the target temperature and the surface temperature of the punch head part in contact with the plate were measured. In addition, forming experiments were carried out according to sheet material temperature (100 ℃, 200 ℃, and 300 ℃) to obtain forming results for each condition. The applicability and feasibility of this technology were confirmed through experimental results.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.45 no.6
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• pp.194-203
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• 2008

Though conventional video surveillance systems such as CCTV depended on operators, recently developed intelligent surveillance systems no longer needed operators. However, these new intelligent surveillance systems have their own problems such as Occlusion, changing scale of target object, and affine. This paper handled information damage caused by changing the scale of the target object among other objects. Due to the change of the scale, the inaccurate information of target can be obtained when we update the background information. To handle this problem, we introduce a solution for information damage caused by problem of changing scale of target object located among other objects. Specifically, we suggest multi-stage sampling particle filter based advanced MSER for object tracking system. Through this method, the problem caused by changing scale of target can be avoided.

• Journal of the Korea Society for Simulation
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• v.25 no.3
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• pp.133-146
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• 2016

To engage multiple missiles in single launcher against multiple targets, launcher system has to operate for optimized launch angle to each target sequentially. If the launch angle sequence is simply defined according to the target assignment order only, overall engagement time would be increased, and even in some engagement scenarios, it could be possible to miss some moving targets being out of proper engagement area. Therefore, the study on methodology for a real-time decision of optimized launch angle sequence is necessary. In this paper, the automatic decision model of launch angle sequence was suggested to minimize total engagement time by analyzing the simulation results of all engagement sequence set for multiple moving target scenario. Performance of proposed methodology for decision of optimal launch angle sequence was verified by comparing with the optimal or suboptimal sequence obtained from simulation results.

• The Journal of the Korea institute of electronic communication sciences
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• v.16 no.5
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• pp.789-798
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• 2021

In this study, for the purpose of collecting and analyzing target-specific RCS data of target signals simulator for verification/improvement of radar system performance, VHF band monostatic/bistatic RCS of civil aircraft(B-747, B-737) and fighter(F-16) models were analyzed by EM simulation tool. In order to reduce the RCS analysis time, the analysis time and RCS data were compared and cross-verified. Also, the analysis range was selected by examining the interpolation error according to the analysis angle resolution. The RCS data obtained for each model were analyzed separately by the incident/reflection elevation angle and frequency. The RCS characteristics according to the shape of the aircraft and the incident/reflection azimuth angle were described. Finally, the statistical RCS distribution value of each model is presented through RCS distribution histogram analysis. In the future, the RCS database obtained by this study will be used for the target signals simulator of the VHF band radar system.

• Nuclear Engineering and Technology
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• v.56 no.1
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• pp.147-159
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• 2024

Plutonium-238 has always been considered as the one of the promising radioisotopes for space nuclear power supply, which has long half-life, low radiation protection level, high power density, and stable fuel form at high temperatures. The industrial-scale production of ²³⁸Pu mainly depends on irradiating solid ²³⁷NpO₂ target in high flux reactors, however the production process faces problems such as large fission loss and high requirements for product quality control. In this paper, a conceptual design study of producing ²³⁸Pu in a multi-purpose high flux reactor was evaluated and analyzed, which includes a sensitivity analysis on ²³⁸Pu production and a further study on the irradiation scheme. It demonstrated that the target structure and its location in the reactor, as well as the operation scheme has an impact on ²³⁸Pu amount and product quality. Furthermore, the production efficiency could be improved by optimizing target material concentration, target locations in the core and reflector. This work provides technical support for irradiation production of ²³⁸Pu in high flux reactors.

• Journal of IKEEE
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• v.8 no.1 s.14
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• pp.39-46
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• 2004

This paper presents the realization schemes for a multipurpose coherent mono-pulse radar Simulator with extendable features. We developed and installed the TSG(Timing Signal Generator) board which can simulate a mechanically rotate signal of antenna, an operation timing signal of pulse radar and target signal, to operate the simulator without real target in the indoor environment. Also, with the insertion of the radar signal processor, it came to be easy to achieve the addition of radar function algorithms, to rebuild or extend the multi-DSP Architecture into the simulator. Throughout the simulation results, we verified that the designed coherent mono-pulse radar simulator can exactly display a moving target on the realistic monitor(RD 9800).

• Nuclear Engineering and Technology
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• v.38 no.4
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• pp.327-342
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• 2006

Radiation therapy is an important part of cancer treatment in which cancer patients are treated using high-energy radiation such as x-rays, gamma rays, electrons, protons, and neutrons. Currently, about half of all cancer patients receive radiation treatment during their whole cancer care process. The goal of radiation therapy is to deliver the necessary radiation dose to cancer cells while minimizing dose to surrounding normal tissues. Success of radiation therapy highly relies on how accurately 1) identifies the target and 2) aim radiation beam to the target. Both tasks are strongly dependent of imaging technology and many imaging modalities have been applied for radiation therapy such as CT (Computed Tomography), MRI (Magnetic Resonant Image), and PET (Positron Emission Tomogaphy). Recently, many researchers have given significant amount of effort to develop and improve imaging techniques for radiation therapy to enhance the overall quality of patient care. For example, advances in medical imaging technology have initiated the development of the state of the art radiation therapy techniques such as intensity modulated radiation therapy (IMRT), gated radiation therapy, tomotherapy, and image guided radiation therapy (IGRT). Capability of determining the local tumor volume and location of the tumor has been significantly improved by applying single or multi-modality imaging fur static or dynamic target. The use of multi-modality imaging provides a more reliable tumor volume, eventually leading to a better definitive local control. Image registration technique is essential to fuse two different image modalities and has been In significant improvement. Imaging equipments and their common applications that are in active use and/or under development in radiation therapy are reviewed.

• The Journal of Korea Robotics Society
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• v.6 no.3
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• pp.237-246
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• 2011

Robots have been used in many fields due to its performance improvement and variety of its functionality, to the extent which robots can replace human tasks. Individual feature and better performance of robots are expected and required to be created. As their performances and functions have increased, systems have gotten more complicated. Multi mobile robots can perform complex tasks with simple robot system and algorithm. But multi mobile robots face much more complex driving problem than singular driving. To solve the problem, in this study, driving algorithm based on the energy method is applied to the individual robot in a group. This makes a cluster be in a formation automatically and suggests a cluster the automatic driving method so that they stably arrive at the target. The energy method mentioned above is applying attractive force and repulsive force to a special target, other robots or obstacles. This creates the potential energy, and the robot is controlled to drive in the direction of decreasing energy, which basically satisfies lyapunov function. Through this method, a cluster robot is able to create a formation and stably arrives at its target.