• Structural Engineering and Mechanics
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• v.17 no.3_4
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• pp.557-572
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• 2004

Control systems are used to limit structural lateral deflections during large external loads such as winds and earthquakes. Most recently, the semi-active control approach has grown in popularity due to inexpensive control devices that consume little power. As a result, recently designed control systems have employed many semi-active control devices for the control of a structure. In the future, it is envisioned that structural control systems will be large-scale systems defined by high actuation and sensor densities. Decentralized control approaches have been used to control large-scale systems that are too complex for a traditional centralized approach, such as linear quadratic regulation (LQR). This paper describes the derivation of energy market-based control (EMBC), a decentralized approach that models the structural control system as a competitive marketplace. The interaction of free-market buyers and sellers result in an optimal allocation of limited control system resources such as control energy. The Kajima-Shizuoka Building and a 20-story benchmark structure are selected as illustrative examples to be used for comparison of the EMBC and centralized LQR approaches.

• Smart Structures and Systems
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• v.4 no.5
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• pp.531-548
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• 2008

Recently, dense sensor instrumentation for structural health monitoring has motivated the need for novel passive wireless sensors that do not require a portable power source, such as batteries. Using a layer-by-layer self-assembly process, nano-structured multifunctional carbon nanotube-based thin film sensors of controlled morphology are fabricated. Through judicious selection of polyelectrolytic constituents, specific sensing transduction mechanisms can be encoded within these homogenous thin films. In this study, the thin films are specifically designed to change electrical properties to strain and pH stimulus. Validation of wireless communications is performed using traditional magnetic coil antennas of various turns for passive RFID (radio frequency identification) applications. Preliminary experimental results shown in this study have identified characteristic frequency and bandwidth changes in tandem with varying strain and pH, respectively. Finally, ongoing research is presented on the use of gold nanocolloids and carbon nanotubes during layer-by-layer assembly to fabricate highly conductive coil antennas for wireless communications.

• Journal of Microbiology and Biotechnology
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• v.12 no.1
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• pp.77-83
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• 2002

A bacterial consortium capable of utilizing a variety of polycyclic aromatic hydrocarbons has been isolated from a former manufactured gas plant site. The consortium consisted of four members including Arthrobacter sp., Burkholderia sp., Ochrobacterium sp., and Alcaligenes sp., which were identified and characterized by the patterns of fatty acid methyl esters (FAME analysis) and carbon source utilization (BIOLOG system). With the individual members, the biodegradation characteristics of aromatic hydrocarbons depending on different growth substrates were determined. FAME analyses demonstrated that microbial fatty acid profiles changed to significant extents in response to different carbon sources, and hence, such shift profiles may be informative to characterize the biodegradation potential of a bacterium or microbial community.

• Proceedings of the KSRS Conference
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• v.2
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• pp.1003-1006
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• 2006

Frontal regions in midlatitude storms exhibit a wide range of behavior, which can be observed by remote sensors. These include decay, strengthening, rotating, and sometimes spawning of new cyclones. Here we refine and apply recent theories of front and frontal wave development to a case of a front clearly observed and analyzed in remote sensing data. By applying innovative analysis techniques to the data we assess the respective roles of ageostrophy, background deformation, and Boundary Layer processes in determining the evolution of the surface front. Our analysis comprises of diagnosis of the terms appearing in the vorticity and divergence equations using remotely sensed observations.

• Journal of the Korean Ceramic Society
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• v.46 no.5
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• pp.510-514
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• 2009

The microstructure and mechanical behavior of deformed silicon were characterized using transmission electron microscopy and nanoindentation. Structural defects such as stacking faults and dislocations were observed through the diffraction contrast in transmission electron microscopy. The mechanical properties of deformed Si and 111 Si wafer and mechanical behaviors during contact loading were also characterized using nanoindentation. The hardness values of silicon samples were ${\sim}10$ GPa and the elastic modulus were varied with indentation conditions. Elbow or pop-out behaviors were found in load-displacement curves of silicon samples during nanoindentation. Deformed silicon showed 'pop-out' behavior more frequently under the load of 10 mN, which is attributed to the structural defects in deformed silicon.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09a
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• pp.150-151
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• 2006

Laser pyrolysis is a very suitable method for the synthesis of a wide range of nanoparticles. A pilot unit based on this process has been recently developed at CEA. This paper reports results showing the possibility to produce SiC and $TiO_2$ nanoparticles at rates of respectively 1 and 0.2 kg/h and also the possibility to adjust the mean grain size of the particles and their structure by changing the laser intensity and reactants flow rates. First tests of liquid recovery have been also successfully performed to limit the risks of nanoparticles dissemination in the environement during their recovery.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1997.10a
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• pp.385-390
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• 1997

In recent years there has been an increasing emphasis on shortening design cycles for bringing products to market. This requires the development of computer aided engineering tools which allow analysts to quickly evaluate the effect of design changes on noise, vibration, and harshness. Statistical Energy Analysis (SEA) modeling is a valuable tool for predicting noise and vibration as SEA models are inherently simpler and more robust than deterministic models. SEA modeling can be combined with design sensitivity analysis (DSA) to identify design changes which give the largest performance benefit. This paper describes SEA modeling of an equipment cab. SEA predictions are compared to test data, showing good agreement. The use of design sensitivity analysis in improving cab design is then demonstrated.

• Asian Journal for Public Opinion Research
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• v.10 no.4
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• pp.277-292
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• 2022

Cognizant of the role of the family in influencing health behaviors among its young members, especially during the time of COVID-19 in the Philippines where stay-at-home measures were in place from March 2020 until March 2022, this study sought to determine the predictive relationship of family relationship to COVID-19 preventive behavioral intention and pandemic fatigue among young Filipino undergraduates. A total of 1,665 undergraduate students participated in this cross-sectional online survey. Findings reveal that family cohesion significantly increases COVID-19 prevention behavioral intention among undergraduates. Moreover, students who report high levels of conflict in the family are less likely to comply with preventive behaviors and exhibit higher levels of pandemic fatigue.

• International Journal of Computer Science & Network Security
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• v.21 no.9
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• pp.354-357
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• 2021

Software vulnerabilities are becoming more and more increasing, their role is to harm the computer systems of companies, governmental organizations and agencies. The main objective of this paper is to propose a method that will cluster future software vulnerabilities that may spread. This method is developed by combining the Multiple Correspondence Analysis (MCA), the Elbow procedure and the Kmeans Algorithm. A simulation was done on a dataset of 15713 observations. This simulation allowed us to identify families of future vulnerabilities. This model was evaluated using the silhouette index.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2009.04a
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• pp.106-109
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• 2009

본 논문에서는 교량의 상태감시 테스트베드 구축을 위한 한-미 국제공동연구의 현황 및 활동 내용들을 논하였다. 이 국제공동연구는 최첨단 센서와 구조건전도 모니터링 방법의 유용성 및 통합화하는데 그 목적을 두고 있다. 테스트베드 구축을 위해 가속도계과 동적 FBG 센서, 압전 센서 등과 같은 스마트 센서를 사용하였으며, 무선 데이터수집 시스템이 도입되었다. 교량 모니터링 기법으로는 압전 센서 및 EM센서로부터 취합된 데이터를 이용하여 국부손상검색을 수행하였으며, 가속도계, 동적 FBG센서 및 이미지 프로세싱을 이용하여 진동기반 전역손상검색을 수행하였다. 테스트베드 교량으로는 PC박스 거더교, 강상자형교, 강판형교, 사장교의 4가지 형식의 교량이 사용되었다. 테스트베드 교량에 최신 이동통신 인터넷 연결기술을 이용하여 교량에 설치된 센서로부터 취합된 데이터와 모니터링 시스템으로부터 교량의 상태를 실시간 감시할 수 있는 네트워크 시스템을 구축하였다. 이러한 원거리 이동통신시스템을 통하여 구조물의 건전성 평가결과를 실시간으로 전송 및 분석할 수 있도록 하였다.