• Smart Structures and Systems
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• 제7권2호
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• pp.133-152
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• 2011

System identification is a fundamental step towards the application of structural health monitoring and damage detection techniques. On this respect, the development of evolved identification strategies is a priority for obtaining reliable and repeatable baseline modal parameters of an undamaged structure to be adopted as references for future structural health assessments. The paper presents the identification of the modal parameters of the Guangzhou New Television Tower, China, using a data-driven stochastic subspace identification (SSI-data) approach complemented with an appropriate automatic mode selection strategy which proved to be successful in previous literature studies. This well-known approach is based on a clustering technique which is adopted to discriminate structural modes from spurious noise ones. The method is applied to the acceleration measurements made available within the task I of the ANCRiSST benchmark problem, which cover 24 hours of continuous monitoring of the structural response under ambient excitation. These records are then subdivided into a convenient number of data sets and the variability of modal parameter estimates with ambient temperature and mean wind velocity are pointed out. Both 10 minutes and 1 hour long records are considered for this purpose. A comparison with finite element model predictions is finally carried out, using the structural matrices provided within the benchmark, in order to check that all the structural modes contained in the considered frequency interval are effectively identified via SSI-data.

• 한국안전학회지
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• 제31권4호
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• pp.120-125
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• 2016

Usually, a risk can be expressed as a product of likelihood and consequence of a hazard factor. Therefore, conventional risk assessment is carried out by frequency analysis and severity analysis, in turns. However, it is well known that intuitive thinking is another excellent way of thinking of human beings. This study aimed to confirm whether there exist any difference in risk assessment results derived by two different procedures - intuitive and analytical. Thus, the present study showed 10 different illustrations to 30 undergraduate students. Their responses were organized as fuzzy membership functions, and summarized as risk assessments, and compared. The results were also verified with the help of statistical hypothesis testing, which showed no significant difference. On the contrary, however, similarity measure used in fuzzy set theory was not credible as anticipated. Many cases failed to satisfy statistical hypothesis even with similarity measure higher than 0.60 so that only a trend could be accepted. In addition, a subject showed a somewhat consistent logical discrepancy in his response, which implied the necessity of sincere analysis in fuzzy formulations.

• 컴퓨터교육학회논문지
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• 제10권2호
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• pp.89-100
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• 2007

대규모 집단을 대상으로 시행하는 서답형 문항을 수기 채점 방식으로 채점하는 경우 채점 과정에서 발생하는 채점 오차를 줄이기 위해서는 많은 노력과 시간을 필요로 한다. 이러한 문제점을 해결하기 위해 세계 각국에서는 서답형 문항 채점 시스템을 개발하여 운용하고 있지만, 국내에서는 채점 시스템의 기초적인 연구도 미흡한 실정이다. 본 연구의 목적은 '서답형 문항의 인터넷 기반 채점 시스템' 설계의 기반을 마련하는데 있다. 시스템 설계의 기반 마련을 위한 시스템의 개요와 기본 설계도, 채점자 배정 방법, 채점자 신뢰도 추정에 의한 채점자 오류 검색 알고리즘을 제안하였다. 본 시스템은 실시간으로 채점 신뢰도를 추정하여 채점 오차를 보정할 수 있는 장점이 있다.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• 제14권1호
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• pp.33-44
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• 2011

The influence of nutrition during early life on physical growth as well as mental development has been thoroughly discussed in the literature. The physical dimensions of the body are greatly influenced by nutrition, particularly during the period of rapid growth in early childhood. Nutritional status affects every pediatric patient's response toillness. Good nutrition is important for achieving normal growth and development. It is indicated that permanent impairment of the central nervous system may result from dietary restriction of imbalance during certain periods of life. If children under 3 years of age show a good nutritional status, it may be assumed that they are well nourished. Several common diseases of children such as iron deficiency, chronic constipation and atopic dermatitis are known food related diseases. Patients with chronic illness and those at risk of malnutrition should have detailed nutritional assessments done. Components of a complete nutritional assessment include a medical history, nutritional history including dietary intake, physical examination, anthropometrics (weight, length or stature, head circumference, midarm circumference, and triceps skinfold thickness), pubertal staging, skeletal maturity staging, and biochemical tests of nutritional status. The use of age, gender, and disease-specific growth charts is essential in assessing nutritional status and monitoring nutrition interventions. Nutrition assessment and dietary counseling is helpful for the cure of disease, and moreover, the prevention of illness.

• 한국초등과학교육학회지:초등과학교육
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• 제32권2호
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• pp.139-158
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• 2013

This study investigated elementary students' (grade 4~6) learning progressions for water cycling drawn from iterative assessments using ordered multiple-choice (OMC) items. An assessment system, which consisted of construct map, item design, outcome space, and measurement model, was employed in this study to examine children's learning progressions. At the first stage of the assessment system, a construct map was designed on which children's conceptual understandings from naive to most sophisticated were represented. At the item design stage, 8 OMC items were drawn from the construct map. Each item option of the OMC items was scored from 0 to 3 according to its level of understanding at the stage of outcome space. As a measurement model, Rasch model, a branch of item response theory, was applied to interpreting the outcomes of the OMC items. This cycle of assessment system was furtherly implemented iteratively in order to elaborate on the first version of water cycling learning progression. In conclusion, children's understanding of water cycling could be described in two aspects: water distribution and water movement. We identified children's conjectural developmental pathways about water cycling existed from superficial and naive accounts to more complex and abstract accounts.

• Smart Structures and Systems
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• 제19권5호
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• pp.499-512
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• 2017

Traditional structural dynamic analysis and Structural Health Monitoring (SHM) of large scale concrete civil structures rely on manufactured embedding transducers to obtain structural dynamic properties. However, the embedding of manufactured transducers is very expensive and low efficiency for signal acquisition. In dynamic structural analysis and SHM areas, piezoelectric transducers are more and more popular due to the advantages like quick response, low cost and adaptability to different sizes. In this paper, the applicable feasibility assessment of the designed "artificial" piezoelectric transducers called Concrete Piezoelectric Smart Module (CPSM) in dynamic structural analysis is performed via three major experiments. Experimental Modal Analysis (EMA) based on Ibrahim Time Domain (ITD) Method is applied to experimentally extract modal parameters. Numerical modal analysis by finite element method (FEM) modeling is also performed for comparison. First ten order modal parameters are identified by EMA using CPSMs, PCBs and FEM modeling. Comparisons are made between CPSMs and PCBs, between FEM and CPSMs extracted modal parameters. Results show that Power Spectral Density by CPSMs and PCBs are similar, CPSMs acquired signal amplitudes can be used to predict concrete compressive strength. Modal parameter (natural frequencies) identified from CPSMs acquired signal and PCBs acquired signal are different in a very small range (~3%), and extracted natural frequencies from CPSMs acquired signal and FEM results are in an allowable small range (~5%) as well. Therefore, CPSMs are applicable for signal acquisition of dynamic responses and can be used in dynamic modal analysis, structural health monitoring and related areas.

• 지식경영연구
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• 제18권1호
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• pp.117-138
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• 2017

While prior work has noted the importance of knowledge creation in gaining competitive advantages, much less is understood about why firms do not actually use what they create. Building upon institutional approaches to organization studies, we offer a new framework to explain the gap between knowledge creation and utilization. We test our framework in an empirical context of sustainable innovation and environmental technologies where ideas of environmental sustainability have recently gained public popularity and shaped how interested audiences make evaluative assessments of firms. In such a context, firms are apt to perceive the social attention toward sustainability to be a normative pressure, which causes them to create new knowledge and develop technologies consistent with the pressure. Using data from the government-initiated certification system for green technologies, our study finds that firms do not always fully implement new environmental technologies they develop in response to the certification program, the situation we refer to as knowledge decoupling. We also examine a set of conditions under which knowledge decoupling becomes more or less amplified. Taken together, our findings show how a firm's knowledge creation and utilization is shaped by its external institutional environment as well as internal learning processes.

• 한국소음진동공학회논문집
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• 제21권10호
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• pp.883-889
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• 2011

The brand sound of vehicle diesel engine is recently one of the important advantage strategies in the automotive company. Because various noise components masked under high frequency level can be audible in quieter driving situation. Many researches have been carried out for subjective and objective assessments on vehicle sounds and noises. In particular, the interior sound quality has been one of research fields that can give high quality feature to vehicle products. Vehicle interior noise above 500 Hz is usually controlled by sound package parts. The materials and geometries of sound package parts directly affect on this high frequency noise. This paper describes the sound quality evaluation method for the vehicle diesel engine noise to establish objective criteria for sound quality assessment. Considering the sensitivity of human hearing to impulsive sounds such as diesel noise, the human auditory mechanism was simulated by introducing temporal masking in the time domain. Furthermore, each of the human auditory organs was simulated by computer codes, providing reasonable analytical explanations of typical human hearing responses to diesel noise. This method finally provides the sound quality index of vehicle diesel engine noise that includes high frequency intermittent offensive sounds caused by impacting excitations of combustion and piston slap.

• Smart Structures and Systems
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• 제16권3호
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• pp.521-535
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• 2015

Vibration-based monitoring is one approach used to perform structural condition assessment. By measuring structural response, such as displacement, dynamic characteristics of a structure may be estimated. Often, the primary dynamic responses in civil structures are below 5 Hz, making accurate low frequency measurement critical for successful dynamic characterization. In addition, static deflection measurements are useful for structural capacity and load rating assessments. This paper presents a DC coupled continuous wave radar to accurately detect both dynamic and static displacement. This low-cost radar sensor provides displacement measurements within a compact, wireless unit appropriate for a range of structural monitoring applications. The hardware components and operating mechanism of the radar are introduced and a series of laboratory experiments are presented to assess the performance characteristics of the radar. The laboratory and field experiments investigate the effect of factors such as target distance, motion amplitude, and motion frequency on the radar's measurement accuracy. The results demonstrate that the radar is capable of both static and dynamic displacement measurements with sub-millimeter accuracy, making it a promising technology for structural health monitoring.

• Journal of the Korean Academy of Child and Adolescent Psychiatry
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• 제26권1호
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• pp.45-51
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• 2015

Objectives : Children with attention-deficit hyperactivity disorder (ADHD) have been shown to display more inhibitory deficits and executive function deficits. This study investigated the treatment effects of neurofeedback (NF) training on executive function by comparing the results of neuropsychological tests of the trained children at pre- and post-training. Methods : Fifteen children with ADHD, aged 6 to 14 years, participated in the study. The NF treatment consisted of slow cortical potential (SCP) training and these sessions took place once a week. The ADHD children performed 20 sessions of NF training within 6 months. Pre-training and post-training assessments encompassed Continuous Performance Test (CPT), Stroop Test, Children's Color Trails Test I&II (CCTT) and Wisconsin Card Sorting Test (WCST). Results : Patients receiving NF training showed significant improvement in visual commission error and standard deviation of auditory response time on CPT ; and total errors on WCST. But there was no significant improvement in the Stroop test and CCTT. Conclusion : SCP training using NF improves the self-regulatory capacities and impulsivity in ADHD patient, especially impulsivity in visual stimulation tasks. This study showed evidence of clinical efficacy of NF on executive function in ADHD.