• Structural Engineering and Mechanics
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• 제62권5호
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• pp.631-642
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• 2017

Accurate actuator tracking plays an important role in real-time hybrid simulation (RTHS) to ensure accurate and reliable experimental results. Frequency-domain evaluation index (FEI) interprets actuator tracking into amplitude and phase errors thus providing a promising tool for quantitative assessment of real-time hybrid simulation results. Previous applications of FEI successfully evaluated actuator tracking over the entire duration of the tests. In this study, FEI with moving window technique is explored to provide post-experiment localized actuator tracking assessment. Both moving window with and without overlap are investigated through computational simulations. The challenge is discussed for Fourier Transform to satisfy both time domain and frequency resolution for selected length of moving window. The required data window length for accuracy is shown to depend on the natural frequency and structural nonlinearity as well as the ground motion input for both moving windows with and without overlap. Moving window without overlap shows better computational efficiency and has potential for future online evaluation. Moving window with overlap however requires much more computational efforts and is more suitable for post-experiment evaluation. Existing RTHS data from Network Earthquake Engineering Simulation (NEES) is utilized to further demonstrate the effectiveness of the proposed approaches. It is demonstrated that with proper window size, FEI with moving window techniques enable accurate localized evaluation of actuator tracking for real-time hybrid simulation.

• Structural Engineering and Mechanics
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• 제71권6호
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• pp.751-761
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• 2019

Lamb wave technology is a promising technology in the field of structural health monitoring and can be applied in the detection and monitoring of defects in plate structures. Based on the reconstruction algorithm for the probabilistic inspection of damage (RAPID), a Lamb-based detection and evaluation method of through-thickness rectangular notches in metal plates was proposed in this study. The influences of through-thickness rectangular notch length and the angle between sensing path and notch length direction on signals were further explored through simulations and experiments. Then a damage index calculation method which focuses on both phase and amplitude difference between detected signals and baseline signals was proposed. Based on the damage index difference between two vertically crossed sensing paths which pass through the notch in a sensor network, the notch direction identification method was proposed. In addition, the notch length was determined based on the damage index distribution along sensing paths. The experimental results showed that the image reconstructed with the proposed method could reflect the information for the evaluation of notches.

• 대한안전경영과학회지
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• 제16권1호
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• pp.119-127
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• 2014

This study tried to develop a basis for quantitative index of working postures associated with WMSDs (Work-related Musculoskeletal Disorders) that could overcome realistic restriction during application of typical checklists for WMSDs evaluation. The baseline data(for a total of 603 jbs) for this study was obtained from automobile manufacturing company. Specifically, data for back posture was analyzed in this study to have a better and more objective method in terms of job relevance than typical methods such as OWAS, RULA, and REBA. Major statistical tools were clustering, logistic regression and so on. The main results in this study could be summarized as follows; 1) The relationship between working posture and WMSDs symptom at back was statistically significant based on the results from logistic regression, 2) Based on clustering analysis, three levels for WMSDs risk at back were produced for flexion as follows: low risk(< $18.5^{\circ}$), medium risk($18.5^{\circ}{\sim}36.0^{\circ}$), high risk(> $36.0^{\circ}$), 3) The sensitivities on risk levels of back flexion was 93.8% while the specificities on risk levels of back flexion was 99.1%. The results showed that the data associated with back postures in this study could provide a good basis for job evaluation of WMSDs at back. Specifically, this evaluation methodology was different from the methods usually used at WMSDs study since it tried to be based on direct job relevance from real working situation. Further evaluation for other body parts as well as back would provide more stability and reliability in WMSDs evaluation study.

• Journal of Korean Neurosurgical Society
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• 제54권3호
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• pp.232-235
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• 2013

Objective : Major complaints of carpal tunnel syndrome (CTS) are sensory components. However, motor deficit also impedes functional status of hand. Contrary to evaluation of sensory function, the objective, quantitative evaluation of median nerve motor function is not easy. The motor function of median was evaluated quantitatively using load cell and its correlation with findings of electrodiagnostic study (EDS) was evaluated. Methods : Objective motor function of median nerve was evaluated by load cell and personal computer-based measurement system. All of the measurement was done in patients diagnosed as having idiopathic CTS by clinical features and EDS findings. The strength of thumb abduction and index finger flexion was measured in each hand three times, and the average value was used to calculate thumb index ratio (TIR). The correlation of TIR with clinical, EDS, and ultrasonographic findings were evaluated. Results : The TIR was evaluated in 67 patients (119 hands). There were 14 males and 53 females, mean age were 57.6 years (range 28 to 81). The higher preoperative nerve conductive studies grade of the patients, the lower TIR was observed [p<0.001, analysis of variance (ANOVA)]. TIR of cases with thenar atrophy were significantly lower than those without (p<0.001, t-test). TIR were significantly lower in patients with severe median nerve swelling in ultrasonography (p=0.042, ANOVA). Conclusion : Measurements of median nerve motor function using load cell is a valuable evaluation tool in CTS. It might be helpful in detecting subclinical motor dysfunction before muscle atrophy develops.

• Agricultural and Biosystems Engineering
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• 제1권1호
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• pp.38-42
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• 2000

Though the freshness for agricultural products is an important factor related to their quality management, this terminology is being used restrictedly because it is very subjective. In this study, a dimensionless index which had the span of the maximum of 1 through the minimum of 0 was proposed to describe freshness of the product with time-variant quality and was applied to Tsugaru and Fuji apples. First, the compressive properties having the linearity in their change regarding time elapsed after harvest were selected. For Tsugaru apple, bio-yield and rupture forces had high correlation with time while for Fuji, bio-yield and rupture deformations had high correlations. When the slope, or ratio of force to deformation, was considered, the effect of cultivar could be neglected. When the linearly time-variant compressive properties for Tsugaru and Fuji apples were involved in the freshness indices, they described well freshness of apples. Also, the freshness decay constant depicted a characteristic which related to freshness decay rate. Therefore, the freshness index can be utilized to manage the quality during storage and distribution of apples.

• 유통과학연구
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• 제13권8호
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• pp.5-14
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• 2015

Purpose - This study undertakes to examine the automotive trade structure between Korea and Russia to accelerate economic cooperation and pinpoint trade discrepancies to increase trade volume through improved policies, eventually finding ways for trade expansion. Research design, data, and methodology - To analyze trade decision factors for both countries, the Index of trade specialization invented by trade specialization theory, is used. Although specific factors should materialize in the trade decision analysis, realistically, concrete explanations are difficult as many unsolved factors are involved as well as their complexities Results - First, to assess comparative market competitiveness, the Index describes A value/B value, representing the Korean versus the Russia market share and the Korean market share versus the world. Second, the index shows that Korea is taking comparative advantage of its export specialization. Third, the RCA indices show considerable improvement compared to 2000. Conclusions - This research used a quantitative approach to examine trade specialization and examined a comparative advantage index of market share to see how inter-trade relations have changed over the past 10 years.

• 한국소음진동공학회논문집
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• 제22권6호
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• pp.509-523
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• 2012

The sound quality based on design optimization, throughout the development process of various electronic office equipments, needs to be considered in order to respond the increased needs for the emotional satisfaction of customers in terms of psycho-acoustics. This paper focuses on how to describe the characteristics of operating sound radiated from laser printers by using various sound attributes, and to model the sound quality index that can properly evaluate the subjective preference on modification conditions in the improvement study quantitatively. Especially, the proposed verification process, in the form of combining the correlation based method and the decision error based method, was applied to improve the generality and reliability of a group of participants in the jury evaluation. The modified Aures tonality model was also proposed to improve the correlation coefficient with the mean response of participants by optimizing some parameters. As a result, the loudness, articulation index, roughness, tonality, fluctuation strength were used to model the sound quality index for laser printers by using the multiple-linear regression method. Through the improvement study, it was confirmed that replacing the absorbing materials is effective to reduce the tonalness radiated from the side of a reference printer model. Based on above results, it can be concluded that the proposed model has enough usefulness as quantitative evaluation index to evaluate the difference between modification conditions in the improvement study.

• 품질경영학회지
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• 제49권3호
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• pp.375-392
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• 2021

Purpose: Regional gaps and conflicts between regions due to Korea's economic development and industrialization have become important issues, and the issue of balanced regional development at regional level has been discussed as the size of the region has increased recently. Although evaluation of regional balance was attempted through various regional balanced development indexes, it is inappropriate as a standard for determining regional balance in Seoul. Therefore, this study aims to develop objective evaluation methodologies and evaluation indicators for balanced development of administrative districts in Seoul, not existing city and national units. Methods: We looked at existing regional balanced development indexes, and suggested a new regional balanced index reflecting regional development, backwardness, and spatial characteristics in Seoul using factor analysis. Results: As a result of factor analysis, the regional balanced development index for administrative districts and administrative dongs consists of two factors (regional revitalization, financial power) and three factors (commercial density, social security demand, regional retardness), respectively. Then the regional balanced development index scores for 116 administrative districts and 423 administrative dongs are calculated by multiplying each factor by a weight obtained through experts' survey. Conclusion: The proposed regional balanced development index can be used as an objective and quantitative basis for regional balanced development within a city. Further research may include continuously adding new indicators that reflect the direction and scale of development.

• Applied Biological Chemistry
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• 제24권4호
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• pp.207-212
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• 1981

제조과정별(製造過程別) 콩나물을 단백질원(蛋白質源)으로 대두(大豆)와 비교(比較)하여 동물사육시험(動物飼育試驗)을 수행(遂行)하고 체중증가(體重增加), 사료효율(飼料效率) 및 단백질효율(蛋白質效率)을 화학적(化學的) 평가(評價)와의 관계(關係)를 검토(檢討)하였다. 1. 생콩(Group A), 4일(日)생콩나물(Group B), 8일(日)생콩나물(Group C), 가열(加熱)한 콩(Group I), 가열(加熱)한 4일(日)콩나물(Group F), 가열(加熱)한 8일(日) 콩나물(Group G), 가열(加熱)한 4일(日) 콩나물자엽(子葉)(Group H) 그리고 가열(加熱)할 4일(日)콩나물배유(胚軸)(Group I)을 각각(各各) 단백질원(蛋白質源))으로 하여 4주간(週間)의 백서생육시험(白鼠生育試驗)에서 체중증가량(體重增加量), 사료섭취량(飼料攝取量) 그리고 단백효율(蛋白效率)(PER)의 크기는 Group E>Group H>Group F>Group G>Group I>Croup A,B 그리고 C의 순(順)으로 나타났다. 2. 체중증가량(體重增加量)은 essential amino acid index (EAAI) 및 requirement index (RI)와는 정(正)의 상관관계(相關關係) ($(r=0.996^{**}$와$r=0.988^{**}$)를 보여 화학적(化學的) 평가(評憤)의 지침(指針)이 될 수 있으나 A/E, A/T, FAO reference protein 그리고 requirement pattern과는 상관관계(相關關係)를 보이지 않았다. EAAI와 RI에 의하면 콩나물의 단백질(蛋白質)의 질(質)은 가열(加熱)한 4일(日)콩이 가장 높았고 가열(加熱)한 4일(日)콩나물자엽(子葉), 가열(加熱)한 4일(日)콩나물중, 가열(加熱)한 8일(日)콩나물, 가열(加熱)한 4일(日)콩나물 배유(胚軸)의 순(順)으로 낮게 나타났다. 3. $25^{\circ}C$에서 4일(日)동안 기른 콩나물의 단백질(蛋白質)의 질(質)을 원료(原料)콩과 비교(比較)해 보면 화학적평가(化學的評價)에서 4.5%의 단백질(蛋白質)의 양적손실(量的損失)과 11%의 질적손실(質的的損失)(EAAI기준)을 일으켰으며 그리고 영양적평가(營養的評價)에서 7%의 단백효율손실(蛋白效率損失)과 18%의 체중손실(體重損失)을 일으켰다.

• 대한인간공학회지
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• 제29권2호
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• pp.203-210
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• 2010

For the development of a better product which fits to the target user population, physical workloads such as reach and visibility are evaluated using digital human simulation in the early stage of product development; however, ergonomic workload assessment mainly relies on visual observation of reach envelopes and view cones generated in a 3D graphic environment. The present study developed a quantitative assessment method of physical workload in a digital environment and applied to the evaluation of a Korean utility helicopter (KUH) cockpit design. The proposed assessment method quantified physical workloads for the target user population by applying a 3-step process and identified design features requiring improvement based on the quantified workload evaluation. The scores of physical workloads were quantified in terms of posture, reach, visibility, and clearance, and 5-point scales were defined for the evaluation measures by referring to existing studies. The postures of digital humanoids for a given task were estimated to have the minimal score of postural workload by finding all feasible postures that satisfy task constraints such as a contact between the tip of the index finger and a target point. The proposed assessment method was applied to evaluate the KUH cockpit design in the preliminary design stage and identified design features requiring improvement. The proposed assessment method can be utilized to ergonomic evaluation of product designs using digital human simulation.