• Structural Engineering and Mechanics
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• 제27권6호
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• pp.697-711
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• 2007

Though extensive research has been carried out for the ultimate strength of steel reinforced concrete (SRC) members under static and cyclic load, there was only limited information on the applied analysis models. Modeling of the inelastic response of SRC members can be accomplished by using a microcosmic model. However, generally used microcosmic model, which usually contains a group of parameters, is too complicated to apply in the nonlinear structural computation for large whole buildings. The intent of this paper is to develop an effective modeling approach for the reliable prediction of the inelastic response of SRC columns. Firstly, five SRC columns were tested under cyclic static load and constant axial force. Based on the experimental results, normalized trilinear skeleton curves were then put forward. Theoretical equation of normalizing point (ultimate strength point) was built up according to the load-bearing mechanism of RC columns and verified by the 5 specimens in this test and 14 SRC columns from parallel tests. Since no obvious strength deterioration and pinch effect were observed from the load-displacement curve, hysteresis rule considering only stiffness degradation was proposed through regression analysis. Compared with the experimental results, the applied analysis model is so reasonable to capture the overall cyclic response of SRC columns that it can be easily used in both static and dynamic analysis of the whole SRC structural systems.

• Structural Engineering and Mechanics
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• 제74권5호
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• pp.711-722
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• 2020

In this study, on-site testing was carried out to investigate the vibration serviceability of a composite steel-bar truss slab with steel girder system. Impulse excitations (heel-drop and jumping) and steady-state motion (walking and running) were performed to capture the primary vibration parameters (natural frequency and damping ratio) and distribution of peak acceleration. The composite floor possesses low frequency (<8.3Hz) and damping ratio (<2.47%). Based on experimental, theoretical, and numerical analyses on fundamental natural frequency, the boundary condition of SCSS (i.e., three edges simply supported and one edge clamped) is deemed more comparable substitutive for the investigated composite floor. Walking and running excitations by one person (single excitation) were considered to evaluate the vibration serviceability of the composite floor. The measured acceleration results show a satisfactory vibration perceptibility. For design convenience and safety, a crest factor β_rp describing the ratio of peak acceleration to root-mean-square acceleration induced from the walking and running excitations is proposed. The comparisons of the modal parameters determined by walking and running tests reveal the interaction effect between the human excitation and the composite floor.

• 대한임베디드공학회논문지
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• 제10권1호
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• pp.13-23
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• 2015

Recently, a few image-processing based mobile urine testers have actively been studied since the urine-analysis result can be available to the user in real time immediately after the test is done. However, the accuracy of test result can be severely degraded due to variable illumination environments and a variety of manners to capture the image with a camera embedded in the smartphone according to different users. This paper proposes the Check4Urine system, a novel smartphone-based portable urine-analysis tester and provides three techniques to improve such a performance degradation problem robust to various test environments and disturbances, which are the compensation algorithm to correct the varying illumination effect, an urine strip detection algorithm robust to edge loss of the object image, and the color decision algorithm based on the pre-processed reference table. Experimental results show that the proposed Check4Urine system increases the accuracy of urine-analysis by 20-50% at various test conditions, compared with the existing image-processing based mobile urine tester.

• 한국분무공학회지
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• 제16권2호
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• pp.69-75
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• 2011

This article presents computational fluid dynamics (CFD) simulations of sub-micron particle movements and flow characteristics in laboratory-scale electrostatic precipitator (ESP) without corona discharge, and for simulation, it uses the commercial CFD program (CFD-ACE) including electrostatic theory and Lagrangian-based equation for sub-micron particle movement. For validation of CFD results, a simple cylindrical type of ESP is simulated and numerical prediction shows fairly good agreement with the analytical solution. In particular, the present study investigates the effect of particle diameter, inlet flow rate, and applied electric potential on particle collection efficiency and compares the numerical prediction with the experimental data, showing good agreement. It is found that the particle collection efficiency decreases with increasing inlet flow rate because the particle detention time becomes shorter, whereas it decreases with the increase in sub-micron particle diameter and with the decrease of applied electric voltage resulting from smaller terminal electrostatic velocity.

• 대한전자공학회논문지TC
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• 제42권6호
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• pp.33-40
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• 2005

본 논문에서는 광대역 무선 접속 시스템에서 동적 예약 접속 프로토콜의 메시지 지연시간을 해석적으로 분석한다. IEEE 802.16 BWA 와 ETSI HIPERLAN//2 와 같은 광대역 무선 접속 시스템은 무선 MAN 의 시스템 커버리지를 갖으며, 단말의 이동성을 지원하지 않는, 즉 단말이 고정되어 있는 시스템이다. 또한 광대역 무선 접속 시스템에서 사용하는 MAC 프로토콜은 트래픽별 QoS를 효율적으로 지원하기 위하여 경쟁 기반으로 동적 예약을 지원하는 TDMA 방식을 사용한다. 이와 같은 통신망을 분석하기 위하여 경쟁 기반 동적 예약 방식을 지원하는 TDMA 프로토콜의 성능을 해석적으로 분석한다.

• Nuclear Engineering and Technology
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• 제41권1호
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• pp.113-124
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• 2009

The line shape functions for the Doppler-broadened gamma ray spectrum are considered in the $^{10}B(n,{\alpha}{\gamma})^7Li$ reaction occurring in a surrounding medium where the excited $^7Li$ nucleus is slowed down and stopped before decay. The phenomenological form of the stopping power was used for the broadening effect. Convolution with the detailed response of a germanium detector is taken into consideration for the simplest case of solely electronic stopping. A numerical study for the analysis of $^{10}B$ by thermal neutron capture is conducted by performing a parametric search and fitting the measured spectrum in a least-squares approach. In comparison with the previous numerical approach using the same analysis, the computational speed is increased and reliable information concerning the stopping power of the medium is obtained while estimating the uncertainty. Implementation of the routine analysis of $^{10}B$ is facilitated on a recent version of the gamma ray spectrum analysis package HyperGam.

• 센서학회지
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• 제13권2호
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• pp.90-95
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• 2004

Protein and gene detection have been growing importance in medical diagnostics. Field effect transistor (FET) - type biosensors have many advantages such as miniaturization, standardization, and mass-production. In this work, we have fabricated metal-oxide-semiconductor (MOS) FET that operates as molecular recognitions based electronic sensor. Measurements were taken with the devices under phosphate buffered saline solution. The drain current ($I_{D}$) was decreased after forming self-assembled mono-layers (SAMs) used to capture the protein, which resulted from the negative charges of SAMs, and increased after forming protein by 11.5% at $V_{G}$ = 0 V due to the positive charges of protein.

• 한국물환경학회지
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• 제21권1호
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• pp.79-83
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• 2005

Foraging behaviour of false dace, Pseudorasbora parva, was investigated in water flowing at various velocities with the existence of a cavity for rest. The pursuit comprised three succeeding processes such as, approaching, chasing and attacking. Angles between the fish body and the water flow direction and swimming speeds increased in the latter stages of approaching, chasing and attacking. All pursuit angles, swimming speeds and distances increased with flow velocity and peaked at the flow velocity of 7 cm/sec. At higher velocities, however, the fish avoided the use of much energy against the large drag force. The probability of capture and the feeding rate steadily decreased with increasing flow velocity. Under the fast flow, the fish adjusted their swimming speed to get the optimum velocity relative to the flowing water for the energetic budget. Fish spent more time in the cavity as flow velocity increased to avoid the energy expenditure necessitated by the high velocity.

• 한국운동역학회지
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• 제30권3호
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• pp.217-223
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• 2020

Objective: The purpose of this study was to analyze the effect of postural sway on the kinematic variables of the putter head during golf putting and to provide information to the importance of postural sway control in the putting stroke for novice golfers. Method: The center of pressure (CoP) and Kinematics variables of the putter head were calculated during 2 m flat golf putting using 8 motion capture cameras (250 Hz) and 2 force plate (1,000 Hz). SPSS 24.0 was used to perform Pearson's correlation coefficient and simple regression analysis, and the statistically significance level was set to .05. Results: As a result of analyzing the correlation between CoP variables and the putter head rotation angle, the CoP moving length, CoP moving range (ML direction), and CoP moving velocity (ML direction) showed a positive correlation with the putter head rotation angle (yaw axis) and were statistically significant. Conclusion: Therefore, In order to perform the accurate putting stroke maintaining the ball's directionality, it is determined that it is important to control posture sway in the ML directions by minimizing the movement and velocity of the CoP.

• 보건교육건강증진학회지
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• 제27권1호
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• pp.1-8
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• 2010

Objectives: Human papillomavirus (HPV) infection is highly associated with cervical cancer. So, the modification of the risk factors of HPV infection is essential for prevention of cervical cancer. This study was performed to evaluate the risk factors of HPV infection. Methods: HPV test of 12,337 study population conducted using Hybrid-Capture II assay(HC-II) and self-administered questionnaires were collected. The study population was people who visited hospital-based medical screening center from January to December 2007 and all were female employees or employees' partner. Results: In logistic regression analysis, smoking and alcohol drinking were significant factors, with odds ratios of 1.328 (95% CI 1.010~1.746) and 1.644 (95% CI 1.309~2.066), respectively. Nutritional supplements was also significant factor, which odds ratio was 1.161 (95% CI 1.004~1.343). Oral contraceptives was positive association with HPV infection (odds ratio 2.108; 95% CI 1.217~3.652), whereas condom was negative association (odds ratio 0.851; 95% CI 0.740~0.979). Conclusion: HPV Prevalence of 12,377 study population was 11.4%. Smoking, alcohol drinking, nutritional supplements and oral contraceptives were possible risk factors of HPV infection, and condom had possible preventive effect on HPV infection. Further prospective and comprehensive studies about HPV risk factors are required.