• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.24 no.3
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• pp.15-20
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• 2024

Path planning for unmanned aerial vehicles (UAV) is crucial in avoiding collisions with obstacles in complex environments that include both static and dynamic obstacles. Path planning algorithms like RRT and A^* are effectively handle static obstacle avoidance but have limitations with increasing computational complexity in high-dimensional environments. Reinforcement learning-based algorithms can accommodate complex environments, but like traditional path planning algorithms, they struggle with training complexity and convergence in higher-dimensional environment. In this paper, we proposed a reinforcement learning model utilizing a cell decomposition algorithm. The proposed model reduces the complexity of the environment by decomposing the learning environment in detail, and improves the obstacle avoidance performance by establishing the valid action of the agent. This solves the exploration problem of reinforcement learning and improves the convergence of learning. Simulation results show that the proposed model improves learning speed and efficient path planning compared to reinforcement learning models in general environments.

• Journal of Animal Science and Technology
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• v.44 no.4
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• pp.459-474
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• 2002

The purpose of this study was to establish the optimal operation condition of the natural evaporation system(NES) which was used for reducing swine slurry. Especially the main point of this study is to estimate the effect of climate condition(clear & rainy) and spray type(batch & flow) for the evaporation rate of swine slurry applying the NES in summer. Experiment was performed from June to August, which was generally regarded as summer in Korea, with the spray type of batch in 2000 and that of flow in 2001. As a result of experiment for batch and flow type, the averaged evaporation rate was measured into 2.71 and 3.59 l/ton . $m^2$ . day on clear days and 0.62 and 0.66 l/ton . $m^2$ . day on raint days, respectively. Based on the calculated evaporation rate by the climate condition and the spray type, it was proved that the averaged reduction rate for total input(1t/day) were 15.99% and 3.19% on clear and rainy days and the evaporation rate of the flow type was superior to that of the batch type by 5%, approximately. Therefore, it was concluded that the supplementary equipment, such as fan, should by operated in rainy days and the spray type of flow rather than that of batch should be recommended to increase the evaporation rate in the natural evaporation system(NES).

• Childhood Kidney Diseases
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• v.4 no.2
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• pp.92-101
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• 2000

Purpose : We analyzed the demogaphic data md clinical course of Korean children with chronic renal failure (CRF) observed between 1990 and 1999. Patients and Methods : Questionnaires were mailed to all children's hospitals ail through the country. We asked for primary renal disease age and serum creatinine levels at first presentation with CRF and end-stage renal disease (ESRD), and modes of renal replacement therapy (RRT). Results : 401 children (254 boys, 147 girls) with CRF, defined as a permanent increase of serum creatinine above 1.2 mg/dl for at least 3 months or until death, were identified. This represents an incidence of 3.68 per million child population per year. Of these patients, 22$\%$ on younger than 5 years, 28$\%$ 5 to 10 years and 50$\%$ 10 to 15 year. Eight five $\%$ of the patients could be classified with a primary renal disease. The most frequent cause is glomerulonephritis (36$\%$), followed by chronic pyelonephritis (21$\%$), renal hrpo/dylplasia (9$\%$), and hereditary nephropathies (7$\%$). Reflux nephropathy (16$\%$) was the most common single cause of CRF. ESRD was reached in 70$\%$ of all patient. 99.3$\%$ of these started RRT. Hemodialysis (HD, 42$\%$), peritoneal dialysis (PD, 35$\%$) and transplantation (TP, 23$\%$) were performed as the initial mode of RRT. A total of 161 TPs were performed (159 first grafts, 2 second grafts). A total of 32 patients died. The main causes of death were dialysis related complication in HD patients and infections in PD patients. Survival rate on any form of RRT was 88.7$\%$ during the mean follow-up period of 37 months. Conclusion Major efforts should be directed toward earlier diagnosis and treatment of reflux nephropathy to prevent occurrence of Of. Dialysis and TP have now become well accepted forms of treatment in Korean children with ESRD.

• The Korean Journal of Applied Statistics
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• v.9 no.2
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• pp.135-143
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• 1996

In surveys on certain social problems which are sensitive in nature, many techniques have been introduced in order to protect evasive or untruthful answers. We suggest a multiple trial randomized response technique(MRRT) and it turns out that MRRT is feasible and more efficient by reducing the variance of the estimate than single trial RRT's investigated by Warner(1965), Mangat & Singh(1990), Mangat(1994).

• Proceedings of the Korean Geotechical Society Conference
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• 2007.09a
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• pp.293-304
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• 2007

In 2007, Round Robin Test (RRT) on ground response analyses has been conducted by the technical committee of Soil Dynamics and Geotechnical Earthquake Engineering of Korean Geotechnical Society. Total 14 teams have reported 16 different results. This paper discusses the evaluation of ground response dispersion caused by the difference of input ground motions. In order to determine the characteristics of ground response, this study analysed the peak ground acceleration, predominant period, and response spectrum of reported ground surface motions. The results suggest that ground response dispersion due to the difference of input ground motions can be significant.

• Progress in Superconductivity and Cryogenics
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• v.3 no.2
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• pp.1-4
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• 2001

For the practical use of a superconducting wire to magnet application, it is important to assess the Young modulus and other mechanical properties of HTS tapes. In order to establish a test method of mechanical properties for oxide composite superconductors. tensile tests of Bi-2223 multi- filamentary tapes were carried out at room temperature, as an activity of the International round robin test proposed by the committee of VAMAS/TWA 16-Subrgroup. The tapes consisting of mutli-filamentary showed a three stage tensile behavior. At the initial stage of the stress-streain curve. The elastic deformation existed in a quite nattrow strain region. But the plastic deformation was observed in a wide strain region due to the platic flow of the Ag alloy matrix. The results of RRT were also reported and discussed.

• Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
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• 2001.02a
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• pp.13-16
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• 2001

In the practical sense, it is important to assess the Young modulus and the degradation of $I_{c}$ due to mechanical deformation in HTS tapes for designing superconducting magnets. In order to establish a test method of mechanical properties in oxide composite superconductors, the committee of VAMAS/TWA 16-Subgroup proposed an international round robin test. The first effort has been focused on the multifilamentary Bi-2223 tapes. Eight groups participated in the RRT activity and each group carried out the tensile test by their own professional technique to three kinds of Bi-2223 tapes. The experimental details were reported and discussed for your information.

• Proceedings of the Korea Information Processing Society Conference
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• 2007.11a
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• pp.315-318
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• 2007

랜덤 테스트(RT)는 가능한 입력 도메인에서 임의의 입력 값을 선택하여 테스트 케이스를 생성하고 테스트를 수행하는 기본적인 블랙 박스 테스트 기법이다. 랜덤 테스트의 성능을 향상 시키기 위해서 오류 패턴을 고려한 다양한 Adaptive Random Testing (ART) 알고리즘들이 제안되어 왔다. 그 중 Distance-Based ART (D-ART), Restricted Random Testing (RRT)이 좋은 성능을 보이고 있지만, 수행시간이 너무 느리다는 단점이 있어, 이를 대체할 수 있는 여러 ART 방법들이 제안되고 있다. 그 중, Adaptive Random Testing through Iterative Partitioning (IP-ART)가 가장 좋은 성능과 빠른 수행시간을 보인다. 본 논문에서는 IP-ART 의 성능을 더욱 향상시킬 수 있는 방법을 제안하고, 시뮬레이션을 통하여 향상된 성능을 평가해 보았다.

• Analytical Science and Technology
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• v.13 no.2
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• pp.136-150
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• 2000

For the identification of unknown drugs in biological samples, we attempted rapid high performance thin layer chromatographic method which is sensitive and selective chromatographic analysis of high performance thin layer chromatography (HPTLC) with automated TLC sampler and ultra-violet (UV) scanner. We constructed HPTLC database (DB) on two hundred five drugs by using the data of Rf values and UV spectra (scan 200-360 nm) as well as gas chromatography/mass spectrometry (GC/MS) DB on ninety six drugs by using the data of relative retention time (RRT) on lidocain and mass spectra. After extracting drugs in biological sample by solid phase extraction (Clean Screen ZSDAU020), we applied them to HPTLC and GC/MS DB. Drugs, especially extracted from biological samples, showed good matching ratio to HPTLC DB and these drugs were confirmed by GC/MS. In conclusion, this DB system is thought to be very useful method for the screening of unknown drugs in biological samples.

• Journal of Korea Game Society
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• v.15 no.4
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• pp.29-38
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• 2015

In the stealth game design, level designers are to develop many interesting game environments with a variety of difficulties. J. Tremblay and his co-authors developed a Unity-based level design tool to help and automate this process. Given a map, if the designer inputs several game factors such as guard paths and velocities, their vision, and the player's initial and goal positions, then the tool visualizes simulation results including (clustered) possible paths a player could take to avoid detection. Thus with the help of this tool, the designer can ensure in realtime if the current game factors result in the intended difficulties and players paths, and if necessary adjust the factors. In this note, we present our improvement on this tool in two aspects. First, we integrate a function that if the designer inputs some vertices in the map, then the tool systematically generates and suggests interesting guard paths containing these vertices of various difficulties, which enhances its convenience and usefulness as a tool. Second, we replace the collision-detection function and the RRT-based (player) path generation function, by our new collision-check function and a Delaunay roadmap-based path generation function, which remarkably improves the simulation process in time-efficiency.