• The Journal of Korean Physical Therapy
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• v.26 no.1
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• pp.21-26
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• 2014

Purpose: This study examined the effect of trunk stabilization exercise upon the lumbar stabilization and foot pressure on an unstable surface with back pain. Methods: The subjects of the study were 10 patients who showed the symptom of back pain with excessive lumbar curve. This study was 4 weeks, 30 minutes per session, three times a week for a total of 12 times as a result of exercise radiation imaging device and foot pressure analyzer. Results: The sacrohorizontal angle was statistically significant(p<0.05). Comparison of the difference between static right and left foot pressure ratio analysis was statistically significant(p<0.05). Dynamic right and left foot pressure comparisons for the difference was statistically significant in the analysis (p<0.05). Conclusion: Trunk stabilization exercise and the reduction of the excessive sacrohorizontal angle, and static and dynamic foot pressure imbalance reduced left and right.

• Journal of KIISE:Software and Applications
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• v.37 no.12
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• pp.942-945
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• 2010

In order to reduce the efforts to inspect the reported alarms from a static buffer overflow analyzer, we present an effective method to filter out redundant alarms. In the static analysis, a sequence of multiple alarms are frequently found due to the same cause in the code. In such a case, it is sufficient and reasonable for programmers to examine the first alarm instead of the entire alarms in the same sequence. Based on this observation, we devise a buffer overflow analysis that filters out redundant alarms with our context refinement technique. Our experiment with several open source programs shows that our method reduces the reported alarms by 23% on average.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2001.11a
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• pp.166-171
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• 2001

In order to improve the efficiency of the design process and the quality of the resulting design for the application-based exclusive rolling element bearings, this study propose design methodologies by using a genetic-based combinatorial optimization. By the presence of discrete variables such as the number of rolling element (standard component) and by the engineering point of views, the design problem of the rolling element bearing can be characterized by the combinatorial optimization problem as a fully discrete optimization. A genetic algorithm is used to efficiently find a set of the optimum discrete design values from the pre-defined variable sets. To effectively deal with the design constraints and the multi-objective problem, a ranking penalty method is suggested for constructing a fitness function in the genetic-based combinatorial optimization. To evaluate the proposed design method, a robust performance analyzer of ball bearing based on quasi-static analysis is developed and the computer program is applied to some design problems, 1) maximize fatigue life, 2) maximize stiffness, 3) maximize fatigue life and stiffness, of a angular contact ball bearing. Optimum design results are demonstrate the effectiveness of the design method suggested in this study. It believed that the proposed methodologies can be effectively applied to other multi-objective discrete optimization problems.

• Journal of The Korean Society of Agricultural Engineers
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• v.61 no.3
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• pp.43-53
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• 2019

It is well-known fact that the stone-mastic asphalt (SMA) mixture has shown superior rut resistance, compared with the dense-graded asphalt (DGA) mixture in highway pavements. However, the SMA is measured to be inferior to DGA mixes when tested by well-known high-temperature test methods, such as the wheel tracking (WT), asphalt pavement analyzer, the Marshall Stability and Kim Test. Therefore, this study examined the reasons why it was measured to be inferior, and devised a potential procedure by which the superiority of SMA could be measured at $60^{\circ}C$. The strength against deformation ($S_D$), which was known to show very high correlation with WT results for DGA mixes, was measured by the Kim Test on the specimen confined in the compacted mold. In standard Kim Test, which used the specimen without confinement, the DGA was measured to show higher $S_D$ than the SMA. But by confining specimen, it was found that the $S_D$ of SMA was measured to be higher than that of DGA. Therefore, the confined static test protocol devised in this study was found to be feasible for evaluating rut resistance of SMA mix.

• Proceedings of the Korean Geotechical Society Conference
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• 1999.03a
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• pp.225-232
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• 1999

Construction case of PRD (Percussion Rotary Drill) pipe pile and matters to be attended in construction of PRD pile were reviewed. The compressive and uplifting static pile load tests for PRD piles were performed and, also, analysis by Pile Driving Analyzer was done. Based on these results, bearing components in each resisting part (that is: steel toe, external skin, and internal skin) were measured separately. The measured resisting force was compared to the value calculated by the estimated formula. The pile capacity was mobilized in steel toe area and the external skin friction and the internal friction were not produced. Thus, it could be considered that toe of PRD pile should be supported in hard bearing stratum (for example, the fresh soft rock).

• Proceedings of the Korea Concrete Institute Conference
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• 1998.10c
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• pp.111-116
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• 1998

Most previous wave tests for concrete have been done to evaluate static material properties, and thus there are less works to investigate dynamic material characteristics of concrete, which should be few in Korea. The objective of this experimental work is to investigate dynamic material characteristics of concrete, such as dynamic elastic modulus, dynamic shear modulus, first resonant frequency, dynamic poisson's ratio and etc. A dynamic Signal Analyzer has been used to perform the wave analysis for various dynamic material properties of test specimen. First Fourier transform technique has been carried out on various wave data acquired by the Resonant Column method, which is a kind of nondestructive tests. Wave analysis has been performed based on KS F2437, which is similar to ASTM C607-71 and is identical to JIS A 1127-1976.

• Proceedings of the KIEE Conference
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• 2008.10b
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• pp.411-412
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• 2008

본 논문에서는 차세대원자로인 APR1400(Advanced Power Reactor 1400)의 출력제어방법으로 모델예측제어 알고리즘을 적용하고, 일일부하추종 운전을 하였을 때 최적의 제어기 구현을 위해 제어 로직의 주요 변수인 예측구간, 제어구간, 모델 차수의 변화에 따른 제어 성능을 평가하였다. 성능 평가는 원자로 출력제어 성능 검증시 사용하는 방법으로 제어대상인 차세대 원자로(APR1400)를 3차원 노심해석 전산코드인 MASTER(Multipurpose Analyzer for Static and Transient Effects of Reactor)로 시뮬레이션하여 제어 성능을 평가하였다.

• Proceedings of the Korean Information Science Society Conference
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• 2004.04a
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• pp.934-936
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• 2004

본 논문의 목적은 AES(Advanced Encryption Standard)로 선정된 Rijndael 암호 및 복호 알고리즘을 하드웨어로 설계하고 이를 저비용의 FPGA로 구현하는 것이다. 설계된 AES 암호프로세서는 20만 게이트 급 이하의 FPGA로 구현한다는 비용의 제약 조건 하에서 대용량의 데이터를 암호화, 복호화 하기에 적합한 성능을 가지도록 하였다. 또한 구현 단계에서는 설계한 AES 암호프로세서와 UART 모듈을 동일 FPGA상에서 통합하여 실용성 및 면적 효율성을 보였다. 구현된 Rijndael 암호 프로세서는 20만 게이트를 갖는 Xilinx사의 Spartan-II 계열의 XC2S200 칩 사용시 53%의 면적을 차지하였고, Static Timing Analyzer로 분석한 결과 최대 29.3MHz 클럭에서 동작할 수 있고 337Mbps의 최대 성능을 가진다. 구현된 회로는 실제 FPGA를 이용하여 검증을 수행하였다.

• Proceedings of the Korean Geotechical Society Conference
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• 2000.11a
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• pp.285-292
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• 2000

Though there has been increasing use of large diameter drilled shaft as a foundation structure of bridges, current practice for quality control is to confirm the minimum required load carrying capacity during construction stage. For economic and appropriate design of drilled shaft, it is necessary to evaluate the load transfer mechanism by pile load tests during initial stage of construction and to use the test results as a feedback to a revision of initial design. In this paper, results of load tests peformed at several domestic sites are presented to investigate the load transfer characteristics of large diameter drilled shaft. It was found that most of the load on piles is sustained by shaft friction and that only small portion of the load reaches the bottom of the drilled shaft. Some test results of drilled shaft by Pile Driving Analyzer performed at same sites are also presented to compare the load transfer characteristics interpreted from static pile load tests.

• Journal of the Korea Society for Simulation
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• v.13 no.3
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• pp.21-29
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• 2004

The major objective of this paper is to analyze network vulnerabilities using the SIMVA (SIMualtion-based Vulnerability Analyzer). SIMVA is capable of monitor network status and analyze vulnerabilities automatically. To do this, we have employed the advanced modeling and simulation concepts such as SES/MB (System Entity Structure / Model Base) framework, DEVS (Discrete Event System Specification) formalism, and experimental frame for developing network security models and simulation-based analysis of vulnerability. SIMVA can analyze static vulnerability as well as dynamic vulnerability consistently and quantitatively. In this paper, we verified and tested the capability of application of SIMVA by slammer worm attack scenario.