• Title/Summary/Keyword: Parametric measure

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Sloshing suppression by floating baffle

  • Kang, Hooi-Siang;Md Arif, Ummul Ghafir;Kim, Kyung-Sung;Kim, Moo-Hyun;Liu, Yu-Jie;Lee, Kee-Quen;Wu, Yun-Ta
    • Ocean Systems Engineering
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    • v.9 no.4
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    • pp.409-422
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    • 2019
  • Sloshing is a phenomenon which may lead to dynamic stability and damages on the local structure of the tank. Hence, several anti-sloshing devices are introduced in order to reduce the impact pressure and free surface elevation of liquid. A fixed baffle is the most prevailing anti-sloshing mechanism compared to the other methods. However, the additional of the baffle as the internal structure of the LNG tank can lead to frequent damages in long-term usage as this structure absorbs the sloshing loads and thus increases the maintenance cost and downtime. In this paper, a novel type of floating baffle is proposed to suppress the sloshing effect in LNG tank without the need for reconstructing the tank. The sloshing phenomenon in a membrane type LNG tank model was excited under sway motion with 30% and 50% filling condition in the model test. A regular motion by a linear actuator was applied to the tank model at different amplitudes and constant period at 1.1 seconds. Three pressure sensors were installed on the tank wall to measure the impact pressure, and a high-speed camera was utilized to record the sloshing motion. The floater baffle was modeled on the basis of uniform-discretization of domain and tested based on parametric variations. Data of pressure sensors were collected for cases without- and with-floating baffle. The results indicated successful reduction of surface run-up and impulsive pressure by using a floating baffle. The findings are expected to bring significant impacts towards safer sea transportation of LNG.

Efficiency and Productivity on ICT Industry (ICT 제조업과 서비스업의 효율성과 생산성)

  • Jeong, Boon-Do
    • International Commerce and Information Review
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    • v.16 no.4
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    • pp.55-75
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    • 2014
  • Non-parametric method such as technology efficiency, DEA/Window model and Malmquist Productivity Index (MPI) are used to measure efficiency and productivity of ICT (Information and Communication Technology) manufacturing industry and service industry over the period 2007-2011. The results of this paper indicate following: (1) Technology efficiency of the ICT manufacturing industry were found as the range of 0.34 and 0.39 over the sample period. Technology efficiency of the ICT service industry were found as the range of 0.16 and 0.20 over the sample period. (2) The geometric average of the Malmquist TFP indexes on ICT manufacturing industry indicated the productivity improvement an average of 8.3 percent. The geometric average of the Malmquist TFP indexes on ICT service industry indicated the productivity improvement an average of 1.6 percent. (3) TIER analysis result on ICT manufacturing industry showed that optimal bench marking made by storage devices${\rightarrow}$wireless communication equipment${\rightarrow}$broadcasting equipment${\rightarrow}$radio, recording and playback devices${\rightarrow}$computers, printers, video and audio-visual equipment path. TIER analysis result on ICT service industry indicated that optimal bench marking made by computers and packaged software${\rightarrow}$wired communication${\rightarrow}$communication, information, detection equipment${\rightarrow}$consulting and construction for computer systems integration${\rightarrow}$industrial machinery and equipment rental${\rightarrow}$telecommunications reseller${\rightarrow}$system software development and delivery${\rightarrow}$hosting path.

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The Comparative Study for Software Reliability Models Based on NHPP (NHPP에 기초한 소프트웨어 신뢰도 모형에 대한 비교연구)

  • Gan, Gwang-Hyeon;Kim, Hui-Cheol;Lee, Byeong-Su
    • The KIPS Transactions:PartD
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    • v.8D no.4
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    • pp.393-400
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    • 2001
  • This paper presents a stochastic model for the software failure phenomenon based on a nonhomogeneous Poisson process (NHPP). The failure process is analyzed to develop a suitable mean value function for the NHPP ; expressions are given for several performance measure. Actual software failure data are compared with generalized model by Goel dependent on the constant reflecting the quality of testing. The performance measures and parametric inferences of the new models, Rayleigh and Gumbel distributions, are discussed. The results of the new models are applied to real software failure data and compared with Goel-Okumoto and Yamada, Ohba and Osaki models. Tools of parameter inference was used method of the maximun likelihood estimate and the bisection algorithm for the computing nonlinear root. In this paper, using the sum of the squared errors, model selection was employed. The numerical example by NTDS data was illustrated.

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The Bayesian Analysis for Software Reliability Models Based on NHPP (비동질적 포아송과정을 사용한 소프트웨어 신뢰 성장모형에 대한 베이지안 신뢰성 분석에 관한 연구)

  • Lee, Sang-Sik;Kim, Hee-Cheul;Kim, Yong-Jae
    • The KIPS Transactions:PartD
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    • v.10D no.5
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    • pp.805-812
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    • 2003
  • This paper presents a stochastic model for the software failure phenomenon based on a nonhomogeneous Poisson process (NHPP) and performs Bayesian inference using prior information. The failure process is analyzed to develop a suitable mean value function for the NHPP; expressions are given for several performance measure. The parametric inferences of the model using Logarithmic Poisson model, Crow model and Rayleigh model is discussed. Bayesian computation and model selection using the sum of squared errors. The numerical results of this models are applied to real software failure data. Tools of parameter inference was used method of Gibbs sampling and Metropolis algorithm. The numerical example by T1 data (Musa) was illustrated.

Efficient Point-to-Multipoint ABR Flow Control Algorithm based on Congestion Depth (폭주 정도의 측정을 통한 효율적인 점대 다중점 ABR 흐름 제어)

  • Chung, Hye-Ryoun;Chung, Tai-Myoung
    • The Transactions of the Korea Information Processing Society
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    • v.7 no.9
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    • pp.3002-3010
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    • 2000
  • ATM forum defined several ATM oriented services such as ABR, VBR, CBR, UBR, and others. Among them, ABR service is considered as one of the most appropriate ones in the LAN environment. ABR controls network traffic by using RM cells according to ATM forum standard. In particular, the point-to-multipoint ABR service in general uses consolidation algorithms to solve feedback implosion at the branch point. Consolidation algorithms alleviate propagation delay and network congestion problem: thus, the efficiency of consolidation algorithm is closely related to the network performance. In this paper, we describe the limitation of existing consolidation algorithms based on thorough analysis, and then propose an algorithm that performs better than the existing algorithms. We show that the proposed algorithm improves network performance through a parametric simulation, In our simulation the performance measure is the cell rate which is controlled by exploiting the congestion depth. We also found that the proposed algorithm not only improves efficiency of network, but also eliminates the consolidation noise.

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Preferences of Malaysian Cancer Patients in Communication of Bad News

  • Eng, Tan Chai;Yaakup, Hayati;Shah, Shamsul Azhar;Jaffar, Aida;Omar, Khairani
    • Asian Pacific Journal of Cancer Prevention
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    • v.13 no.6
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    • pp.2749-2752
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    • 2012
  • Background: Breaking bad news to cancer patients is a delicate and challenging task for most doctors. Better understanding of patients' preferences in breaking bad news can guide doctors in performing this task. Objectives: This study aimed to describe the preferences of Malaysian cancer patients regarding the communication of bad news. Methodology: This was a cross-sectional study conducted in the Oncology clinic of a tertiary teaching hospital. Two hundred adult cancer patients were recruited via purposive quota sampling. They were required to complete the Malay language version of the Measure of Patients' Preferences (MPP-BM) with minimal researcher assistance. Their responses were analysed using descriptive statistics. Association between demographic characteristics and domain scores were tested using non-parametric statistical tests. Results: Nine items were rated by the patients as essential: "Doctor is honest about the severity of my condition", "Doctor describing my treatment options in detail", "Doctor telling me best treatment options", Doctor letting me know all of the different treatment options", "Doctor being up to date on research on my type of cancer", "Doctor telling me news directly", "Being given detailed info about results of medical tests", "Being told in person", and "Having doctor offer hope about my condition". All these items had median scores of 5/5 (IQR:4-5). The median scores for the three domains were: "Content and Facilitation" 74/85, "Emotional Support" 23/30 and "Structural and Informational Support" 31/40. Ethnicity was found to be significantly associated with scores for "Content and Facilitation" and "Emotional Support". Educational status was significantly associated with scores for "Structural and Informational Support". Conclusion: Malaysian cancer patients appreciate the ability of the doctor to provide adequate information using good communication skills during the process of breaking bad news. Provision of emotional support, structural support and informational support were also highly appreciated.

Influence of ductility of reinforcement on the plastic hinge formation (철근의 연성이 소성힌지 생성에 미치는 영향)

  • Park, Dae-Gyun;Cho, Jae-Yeol;Park, Sung-Hyun
    • Proceedings of the Korea Concrete Institute Conference
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    • 2008.11a
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    • pp.97-100
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    • 2008
  • Subjected to seismic action causing large deformation of bridge columns, the plastic hinge region is commonly formed in the column end zone. The deformation capacity of a concrete column can be expressed by using plastic hinge length. The mechanical properties of high-strength reinforcing steel is different from that of normal-strength steel and the mechanical properties of steel will influence the plastic hinge formation. Therefore, in other to accurately predict the deformation of concrete column using high-strength steel, the plastic hinge length can be expressed as a function of the mechanical properties of steel such as the tensile to yield strength ratio and the strain at ultimate state. However, little research has been conducted into the effect of mechanical properties of steel on the plastic hinge length. It was difficult to measure the plastic hinge length from the test results. Therefore, the plastic hinge length of concrete columns was investigated from the curvature profile. A numerical approach was used to study the effect of various parameters on plastic hinge length. Based on the results of the numerical parametric study, a new expression for plastic hinge length was proposed.

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Proposal of new ground-motion prediction equations for elastic input energy spectra

  • Cheng, Yin;Lucchini, Andrea;Mollaioli, Fabrizio
    • Earthquakes and Structures
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    • v.7 no.4
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    • pp.485-510
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    • 2014
  • In performance-based seismic design procedures Peak Ground Acceleration (PGA) and pseudo-Spectral acceleration ($S_a$) are commonly used to predict the response of structures to earthquake. Recently, research has been carried out to evaluate the predictive capability of these standard Intensity Measures (IMs) with respect to different types of structures and Engineering Demand Parameter (EDP) commonly used to measure damage. Efforts have been also spent to propose alternative IMs that are able to improve the results of the response predictions. However, most of these IMs are not usually employed in probabilistic seismic demand analyses because of the lack of reliable Ground Motion Prediction Equations (GMPEs). In order to define seismic hazard and thus to calculate demand hazard curves it is essential, in fact, to establish a GMPE for the earthquake intensity. In the light of this need, new GMPEs are proposed here for the elastic input energy spectra, energy-based intensity measures that have been shown to be good predictors of both structural and non-structural damage for many types of structures. The proposed GMPEs are developed using mixed-effects models by empirical regressions on a large number of strong-motions selected from the NGA database. Parametric analyses are carried out to show the effect of some properties variation, such as fault mechanism, type of soil, earthquake magnitude and distance, on the considered IMs. Results of comparisons between the proposed GMPEs and other from the literature are finally shown.

Self-Training Trunk Program for Improving Balance and Walking Ability in People with Chronic Stroke -A Preliminary Study- (만성 뇌졸중 환자의 균형 및 보행 증진을 위한 체간 자가 훈련 프로그램 -예비연구-)

  • Na, Eun-Jin;Woo, Young-Keun
    • PNF and Movement
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    • v.15 no.3
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    • pp.317-331
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    • 2017
  • Purpose: Balance and walking ability are important elements of functional independence for people with stroke and are major goals in rehabilitation. These abilities require trunk performance, but most chronic stroke patients reach a plateau in their rehabilitation. Therefore, the purpose of this study was to investigate the effects of a self-training trunk program to improve balance and walking ability in people with stroke, and to suggest such a self-training program for integrated rehabilitation of people with stroke. Methods: The study recruited 7 people with stroke. The subjects performed trunk training for 30 min per day, 6 days per week, for 3 weeks. Participants were measured on the Trunk Impairment Scale (TIS), the Berg Balance Scale (BBS), the Korean Activities-specific Balance Confidence (K-ABC) scale, the Falls Efficacy Scale (FES), the Functional Gait Assessment (FGA), the 6 Minute Walk Test (6MWT) and a gait analysis to measure the training effects. Statistical analysis used the Wilcoxon signed-rank test as a non-parametric statistical test. Results: TIS was not significantly different after the self-training trunk program, but BBS (p>0.05), K-ABC, and FES were significantly improved after the training program (p<0.05). Furthermore, the 6MWT, stride/height %, and one-leg stance were significantly improved after the training program (p<0.05), but cadence, stance, and swing duration were not significantly different after the training (p>0.05). Conclusion: These results suggest that a self-training trunk program should be integrated into stroke rehabilitation to improve balance and walking ability, and further research is needed to develop the program to be more effective for chronic stroke patients.

Seismic retrofitting by base-isolation of r.c. framed buildings exposed to different fire scenarios

  • Mazza, Fabio;Mazza, Mirko
    • Earthquakes and Structures
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    • v.13 no.3
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    • pp.267-277
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    • 2017
  • Base-isolation is now being adopted as a retrofitting strategy to improve seismic behaviour of reinforced concrete (r.c.) framed structures subjected to far-fault earthquakes. However, the increase in deformability of a base-isolated framed building may lead to amplification in the structural response under the long-duration horizontal pulses of high-magnitude near-fault earthquakes, which can become critical once the strength level of a fire-weakened r.c. superstructure is reduced. The aim of the present work is to investigate the nonlinear seismic response of fire-damaged r.c. framed structures retrofitted by base-isolation. For this purpose, a five-storey r.c. framed building primarily designed (as fixed-base) in compliance with a former Italian seismic code for a medium-risk zone, is to be retrofitted by the insertion of elastomeric bearings to meet the requirements of the current Italian code in a high-risk seismic zone. The nonlinear seismic response of the original (fixed-base) and retrofitted (base-isolated) test structures in a no fire situation are compared with those in the event of fire in the superstructure, where parametric temperature-time curves are defined at the first level, the first two and the upper levels. A lumped plasticity model describes the inelastic behaviour of the fire-damaged r.c. frame members, while a nonlinear force-displacement law is adopted for the elastomeric bearings. The average root-mean-square deviation of the observed spectrum from the target design spectrum together with a suitable intensity measure are chosen to select and scale near- and far-fault earthquakes on the basis of the design hypotheses adopted.