• Title/Summary/Keyword: modeling, modeling and analysis

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Analysis of the Behavior of Tubular-Type Equipment for Nuclear Waste Treatment : Sensitivities of the Parameters Affecting Mass Transfer Yield (방사성폐기물의 화학처리공정에 사용되는 유동관식 장치의 해석 : 물질전달 수율에 미치는 매개변수들의 민감도)

  • Yoo, Jae-Hyung;Lee, Byung-Jik;Shim, Joon-Bo;Kim, Eung-Ho
    • Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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    • v.5 no.1
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    • pp.91-99
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    • 2007
  • It was intended in this study to investigate the effects of various parameters on the chemical reaction or mass transfer yield in a tubular-type nuclear waste treatment equipment. Since such equipments, as a tubular reactor, multistage solvent extractor, and adsorption column, accompany chemical reaction or mass transfer along the fluid-flowing direction, mathematical modeling for each equipment was carried out first. Then their behaviors of the chemical reaction or mass transfer were predicted through computer simulations. The inherent major parameters for each equipment were chosen and their sensitivities. affecting the reaction or mass transfer yield were analyzed. For the tubular reactor, the effects of axial diffusion coefficient and reaction rate constant on the reaction yield were investigated. As for the multistage solvent extractor, the backmixing of continuous phase and the distribution coefficient between fluid and solvent were considered as the major parameters affecting the extraction yield as well as concentration profiles throughout the axial direction of the extractor. For the adsorption column, the equilibrium constant between fluid and adsorbent surface, and the overall mass transfer coefficient between the two phases were taken as the major factors that affect the adsorption rate.

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Voice Activity Detection using Motion and Variation of Intensity in The Mouth Region (입술 영역의 움직임과 밝기 변화를 이용한 음성구간 검출 알고리즘 개발)

  • Kim, Gi-Bak;Ryu, Je-Woong;Cho, Nam-Ik
    • Journal of Broadcast Engineering
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    • v.17 no.3
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    • pp.519-528
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    • 2012
  • Voice activity detection (VAD) is generally conducted by extracting features from the acoustic signal and a decision rule. The performance of such VAD algorithms driven by the input acoustic signal highly depends on the acoustic noise. When video signals are available as well, the performance of VAD can be enhanced by using the visual information which is not affected by the acoustic noise. Previous visual VAD algorithms usually use single visual feature to detect the lip activity, such as active appearance models, optical flow or intensity variation. Based on the analysis of the weakness of each feature, we propose to combine intensity change measure and the optical flow in the mouth region, which can compensate for each other's weakness. In order to minimize the computational complexity, we develop simple measures that avoid statistical estimation or modeling. Specifically, the optical flow is the averaged motion vector of some grid regions and the intensity variation is detected by simple thresholding. To extract the mouth region, we propose a simple algorithm which first detects two eyes and uses the profile of intensity to detect the center of mouth. Experiments show that the proposed combination of two simple measures show higher detection rates for the given false positive rate than the methods that use a single feature.

Design of Sliding Mode Fuzzy Controller for Vibration Reduction of Large Structures (대형구조물의 진동 감소를 위한 슬라이딩 모드 퍼지 제어기의 설계)

  • 윤정방;김상범
    • Journal of the Earthquake Engineering Society of Korea
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    • v.3 no.3
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    • pp.63-74
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    • 1999
  • A sliding mode fuzzy control (SMFC) algorithm is presented for vibration of large structures. Rule-base of the fuzzy inference engine is constructed based on the sliding mode control, which is one of the nonlinear control algorithms. Fuzziness of the controller makes the control system robust against the uncertainties in the system parameters and the input excitation. Non-linearity of the control rule makes the controller more effective than linear controllers. Design procedure based on the present fuzzy control is more convenient than those of the conventional algorithms based on complex mathematical analysis, such as linear quadratic regulator and sliding mode control(SMC). Robustness of presented controller is illustrated by examining the loop transfer function. For verification of the present algorithm, a numerical study is carried out on the benchmark problem initiated by the ASCE Committee on Structural Control. To achieve a high level of realism, various aspects are considered such as actuator-structure interaction, modeling error, sensor noise, actuator time delay, precision of the A/D and D/A converters, magnitude of control force, and order of control model. Performance of the SMFC is examined in comparison with those of other control algorithms such as $H_{mixed 2/{\infty}}$ optimal polynomial control, neural networks control, and SMC, which were reported by other researchers. The results indicate that the present SMFC is an efficient and attractive control method, since the vibration responses of the structure can be reduced very effectively and the design procedure is simple and convenient.

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Implementation of the mobility for Location Searching in Broadband Intelligence Wireless ATM Networks (광대역 지능 무선 ATM 망에서 위치 탐색을 위한 이동성 구현)

  • 정운석;박광채
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.7 no.3
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    • pp.461-467
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    • 2003
  • This paper proposes the method of mobility implementation for location searching in the intelligence wireless ATM networks that expand and apply standard broadband signaling capabilities, and analyze the performance based on the numerical algorithm. The existing B-ISDN UNI protocol stack demands the location search mechanism to determine the location of mobile terminal in the wireless ATM networks because it use single protocol through the fixed PTP interface or PTM interface that don't support terminal mobility. The proposed method make possible the dynamic mobility at a part of wireless access by minimizing the signaling load without a falling-off in system performance by using the intelligence network technology according to the expansion of ATM and B-ISDN signaling integration based on the fixed networks. We implemented the performance analysis by MFC modeling based on numerical algorithm, and realized the efficiency of expenses by carrying out the comparative signaling performance evaluation to measure the relative gains of location search service in the intelligence wireless ATM system. The obtained results have the flexibility to operate in the public B-ISDN network environment without a change of existing B-ISDN/ATM NNI signaling reference to support the wireless ATM access system, and can easily expand to correspond to terminal mobility and various multimedia services in the next broadband PCS.

A Study on the 'Principle-Policy Puzzle' in the Public Opinion of the 'Engagement Policy' (김대중 정부의 통일정책에 대한 여론의 이중성: 원칙과 정책에 대한 의견의 괴리)

  • Rhee, June-Woong
    • Korean journal of communication and information
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    • v.26
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    • pp.291-326
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    • 2004
  • This study explores the process within which whereas the majority of Korean people agree on the principle of the unification policy, the opinions about the concrete policy alternatives related to the principle do not converge. To account for this phenomenon, a.k.a. 'the principle-policy puzzle in public opinion', this study constructs and tests a covariance structural model with the explanatory variables such as political knowledge, political ideology, authoritarian personality, social distance, and the evaluation of the president. In addition, the interaction effects of the interpretive frames regarding the unification policy and political knowledge along with the main effects of socio-demographic variables are tested to explain the degree to which people show the gap between the agreements on the unification principle and policy alternatives. A sample of 600 Seoul people are recruited to provide the data for the analysis of structural equation modeling. Ie was found that the proposed model receives empirical supports from the data. In particular, political knowledge and authoritarian personality play key roles in accounting for the complex process of public opinion in the 'principle-policy puzzle'. The findings were discussed in terms of the representations of the Engagement policy in the mass media and the public perception of them.

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Analysis of Near Field for Base Station Panel Antenna(4 X 2 Dipole Array) (기지국용 판넬 안테나(4 X 2 Dipole Array)의 근역장 분석)

  • Lee, Dugro;Park, Ju-Derk;Choi, Jae-Ic;Kim, Nam
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.15 no.5
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    • pp.473-479
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    • 2004
  • In this paper, power density in near field is calculated about analytic object which has comparatively large volume in considering used wavelength such as cellular base station antenna. Panel sector antenna which is used widespreadly in domestic cellular wireless communication system is modeled and electromagnetic field distribution in reactive near field region is calculated by FDTD (Finite Difference Time Domain) method. After that, antenna gain in far field region is obtain by near to far transformation. Power spectral density in radiated near field is calculated in applying to gain-based model with antenna gain in far field. Finally, compliance distance is obtained in considering the result from radiated near field calculation and basic restrictions on occupational and general public exposure limits in ICNIRP guideline. In the center of main radiating position, the result from gain-based model is -14.55 ㏈m and the result from surface scanning method is -15.75 ㏈m. When the losses from cables and connectors used in measurement are considered, the results from gain-based model and surface scanning method are nearly coincident.

Truck Destination Choice Behavior incorporating Time of Day, Activity duration and Logistic Activity (출발시간, 통행거리 및 물류활동 특성을 고려한 도착지 선택행태분석)

  • Sin, Seung-Jin;Kim, Chan-Seong;Park, Min-Cheol;Kim, Han-Su
    • Journal of Korean Society of Transportation
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    • v.27 no.1
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    • pp.73-81
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    • 2009
  • While various factors in passenger and freight demand analysis affect on destination choice, a key factor, in general. is an attractiveness measure by size variable (e.g., population. employment etc) in destination zone. In order to measure the attractiveness, some empirical studies suggested that disaggregate gravity model are more suitable than aggregate gravity model. This study proposes that truck travelers trip diary data among Korean commodity flow data could be used to estimate the behaviors of incorporating trip departure time, activity duration and attractiveness in destination. As a result, the main findings of size and distance variables coincide with the conventional gravity model having a positive effect of population variable and a negative effect of distance variable. Due to disaggregate gravity modeling, the unique findings of this study reports that small trucks are more likely to choose short distance and early morning, morning peak and afternoon peak departure time choice. On the other hand, large trucks are more likely to choose long distance and night time departure time choice.

Estimating Groundwater Level Variation due to the Construction of a Large Borrow Site using MODFLOW Numerical Modeling (대규모 토취장 개발 예정 지역의 수치모델을 이용한 지하수위 변동 예측)

  • Ryu, Sanghun;Park, Joonhyeong;Kim, Gyoobum
    • Journal of the Korean GEO-environmental Society
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    • v.13 no.10
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    • pp.15-23
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    • 2012
  • A numerical model and field monitoring data are used to estimate a change in groundwater level at a borrow site, which will be constructed at the mountainous area with a large ground excavation in the study area, Hwaseong city. Lithologic data and hydraulic coefficients are collected at 9 boreholes and also groundwater levels are measured at these boreholes and existing wells in the study area. Additionally, groundwater recharge rate for the type of land cover is estimated using water budget analysis; 133.34mm/year for a mountainous area, 157.68mm/year for a farming area, 71.08mm/year for an urbanized area, and 26.06mm/year for a bedrock exposure area. The change in groundwater level in and around a borrow site is simulated with Modflow using these data. The result of a transient model indicates that a removal of high ground (over 40El.m) by an excavation will produce a decrease in groundwater levels, up to 1 m, around a borrow site in 10 years. It also explains that this ground excavation will bring about the decreases of 9.4% and 7.0% for groundwater recharge and surface runoff, respectively, which are the factors causing groundwater level's change. This study shows that it is required to construct the groundwater monitoring wells to observe the change of groundwater near a borrow site.

Lower the Detection Limits of Accelerator Mass Spectrometry

  • John A., Eliades;Song, Jong-Han;Kim, Jun-Gon;Kim, Jae-Yeol;O, Jong-Ju;Kim, Jong-Chan
    • Proceedings of the Korean Vacuum Society Conference
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    • 2013.02a
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    • pp.243-244
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    • 2013
  • Over the past 15 years, several groups have incorporated radio-frequency quadrupole (RFQ) based instruments before the accelerator in accelerator mass spectrometry (AMS) systems for ion-gas interactions at low kinetic energy (<40 eV). Most AMS systems arebased on a tandem accelerator, which requires negative ions at injection. Typically, AMS sensitivity abundance ratios for radioactive-to-stable isotope are limited to Xr/Xs >10^-15, and the range of isotopes that can be analyzed is limited because of theneed to produce rather large negative ion beams and the presence of atomic isobaric interferences after stripping. The potential of using low-kinetic energy ion-gas interactions for isobar suppression before the accelerator has been demonstrated for several negative ion isobar systems with a prototype RFQ system incorporated into the AMS system at IsoTrace Laboratory, Canada (Ontario, Toronto). Requisite for any such RFQ system applied to very rare isotope analysis is large transmission of the analyte ion. This requires proper phase-space matching between the RFQ acceptance and the ion beam phase space (e.g. 35 keV, ${\varphi}3mm$, +-35 mrad), and the ability to control the average ion energy during interactions with the gas. A segmented RFQ instrument is currently being designed at Korea Institute for Science and Technology (한국과학기술연구원, KIST). It will consist of: a) an initial static voltage electrode deceleration region, to lower the ion energy from 35 keV down to <40 eV at injection into the first RFQ segment; b) the segmented quadrupole ion-gas interaction region; c) a static voltage electrode re-acceleration region for ion injection into a tandem accelerator. Design considerations and modeling will be discussed. This system should greatly lower the detection limits of the 6 MV AMS system currently being commissioned at KIST. As an example, current detection sensitivity of 41Ca/Ca is limited to the order of 10^-15 while the 41Ca/Ca abundance in modern samples is typically 41Ca/Ca~10^-14 - 10^-15. The major atomic isobaric interference in AMS is 41K. Proof-of-principal work at IsoTrace Lab. has demonstrated that a properly designed system can achieve a relative suppression of KF3-/41CaF3- >4 orders of magnitude while maintaining very high transmission of the 41CaF3- ion. This would lower the 41Ca detection limits of the KIST AMS system to at least 41Ca/Ca~10^-19. As Ca is found in bones and shells, this would potentially allow direct dating of valuable anthropological archives and archives relevant to our understanding of the most pronounced climate change events over the past million years that cannot be directly dated with the presently accessible isotopes.

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Determinants of Male Police Officers' Investigative Behavior(Active Investigation vs. Secondary Victimization) of Sexual Violence (남성경찰관의 성폭력 수사행동(적극적 수사와 이차폭력) 결정요인 - 성폭력에 대한 편견을 중심으로 -)

  • Lee, Myung-Shin;Yang, Nan-Mee
    • Korean Journal of Social Welfare
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    • v.63 no.1
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    • pp.159-185
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    • 2011
  • This study aims to find out the determinants of male police officers' investigative behavior(active investigation vs. secondary victimization) of sexual violence. For this purpose, a hypothetical model which explains the relationships among the 5 variables (knowledge of law about the investigative role, perception of the protective & connective role, prejudice against the sexual violence, active investigation, and secondary victimization) was developed. Using the data collected from 354 male police officers of 3 cities in Gyeongnam area, the hypothetical model was tested. For data analysis, a structural equation modeling was used, and the final model was found(CFI=0.947, IFI=0.948, RMSEA=0.048). As a result of analyzing the model, the followings were found: (1) Active investigation was increased by knowledge of law about the investigative role, and perception of the protective & connective role, while decreased by prejudice against the sexual violence. (2) Secondary vicimization was decreased by knowledge of law about the investigative role. (3) Prejudice against the sexual violence mediate the effects of knowledge of law about the investigative role, and perception of the protective & connective role on active investigation. (4) Prejudice against the sexual violence was found to have no significant effect on secondary victimization. Based on the findings, multi-educational programs, protocols on investigation of sexual violence, professionalization of the police, and changes in investigation environment as well as a system of collaboration and cooperation between police officer and social worker were suggested as a way to increase active investigation and to decrease secondary victimization.

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