• Title/Summary/Keyword: Technology standard model

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Proposition of a Vibration Based Acceleration Sensor for the Fully Implantable Hearing Aid (완전 이식형 보청기를 위한 진동 기반의 가속도 센서 제안)

  • Shin, Dong Ho;Mun, H.J.;Seong, Ki Woong;Cho, Jin-Ho
    • Journal of rehabilitation welfare engineering & assistive technology
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    • v.11 no.2
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    • pp.133-141
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    • 2017
  • The hybrid acoustic sensor for implantable hearing aid has the structure in which a sound pressure based acoustic sensor (ECM) and a vibration based acceleration sensor are combined. This sensor combines the low frequency sensitivity of an acoustic sensor with the high frequency sensitivity of an acceleration sensor, allowing the acquisition of a wide range of sound from low to high frequency. In this paper, an acceleration sensor for use in a hybrid acoustic sensor has been proposed. The acceleration sensor captures the vibration of the tympanic membrane generated by the acoustic signal. The size of the proposed acceleration sensor was determined to diameter of 3.2 mm considering the anatomical structure of the tympanic membrane and the standard of ECM. In order to make the hybrid acoustic sensor have high sensitivity and wide bandwidth characteristics, the aim of the resonance frequency of the acceleration sensor is to be generated at about 3.5 kHz. The membrane of the acceleration sensor derives geometric structure through mathematical model and finite element analysis. Based on the analysis results, the membrane was implemented through a chemical etching process. In order to verify the frequency characteristics of the implemented membrane, vibration measurement experiment using external force was performed. The experiment results showed mechanical resonance of the membrane occurred at 3.4 kHz. Therefore, it is considered that the proposed acceleration sensor can be utilized for a hybrid acoustic sensor.

Effects of pH and Potassium Chloride in Solvent System of High-Speed Countercurrent Chromatography (pH 및 염화칼륨 첨가가 고속역류크로마토그래피의 용매시스템에 미치는 영향)

  • Lee, Chang-Ho;Lee, Boo-Yong;Lee, Hyun-Yu;Lee, Cherl-Ho
    • Korean Journal of Food Science and Technology
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    • v.29 no.6
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    • pp.1222-1227
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    • 1997
  • Effects of the physical properties of solvent system such as pH and polarity change by salt addition in solvent system were investigated by using high speed countercurrent chromatography apparatus (Model CCC-1000, Pharm-Tech Research Corp. USA). The changes of pH and interfacial tension in solvent system of high speed countercurrent chromatography did not significantly affect on retention of stationary phase, but induced remarkable changes in the partition coefficient of ginkgo flavonoids, kaempferol, quercetin and isorhamnetin. The partition coefficients of ginkgo flavonoid standard increase with an increased pH of solvent system and quercetin sharply increased at pH 10.0. Retention of stationary phase decreases with an increased concentration of KCl in butanol of solvent system. Interfacial tension between two phase in solvent system of hexane increases with an increased concentration of KCl. The polarity of solvent system significantly changes the partition coefficients of ginkgo flavonoid.

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Comparison of Goal-line and In-length Analyses in the Proximity Measures of Simulated Maneuvers (선박조종시뮬레이션의 근접도 평가에서 연속 분석과 목표선 분석에 관한 비교 연구)

  • Lee, Dong-Sup;Jeong, Tae-Gweon
    • Journal of Navigation and Port Research
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    • v.31 no.1 s.117
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    • pp.1-6
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    • 2007
  • The evaluation of safety of simulated maneuvers is frequently analysed by so called goal-line or point of interest in Korea. For the purpose of warning the risk in the proximity measure composed of only the goal-line analysis, this paper utilized Korea Institute of Maritime and Fisheries Technology(KIMFT) which houses a real-time, full-mission shiphandling simulator to examine the goal-line and in-length analyses in the outbound channel of Kwangyang port as an example. It used a 15,000 TEU container ship as a model under environmental conditions of the northwestly 26-knot wind and 2.2-knot ebb current. The result of two analyses showed the probability invading the channel boundary obtained by the goal-line analysis is a little greater than that of the in-length analysis. Therefore it was acknowledged that the proximity measure by the goal-line analysis alone may be followed by some risk. In addition, this paper was to suggest the closest distance to channel boundary from the ship's edge as one of proximity measures, instead of using the ship's deviation from the centerline of channel.

Development of an aequorin-based assay for the screening of corticotropin-releasing factor receptor antagonists (CRF1 길항제 스크리닝을 위한 에쿼린 기반 세포실험 개발연구)

  • Noh, Hyojin;Lee, Sunghou
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.16 no.11
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    • pp.7575-7581
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    • 2015
  • Corticotropin-releasing factor(CRF), one of the stress driven neuropeptides, was widely proposed to influence hair loss and re-growth. For the development of receptor antagonists, the screening system based on intracellular calcium signal process was developed and optimized. The aequorin parental cells were transfected with CRF1 receptor and alpha 16 promiscuous G protein cDNA to establish HEK293a16/hCRF1, a stable cell line for the human CRF1 receptor. In HEK293a16/hCRF1 cells, the range of sauvagine dose response was 12-fold higher($EC_{50}:15.21{\pm}1.83nM$) than in the transiently expressed cells, hence essential conditions for the antagonist screening experiments such as the robust signals and high solvent tolerance were secured. The standard antagonists for the CRF1 receptor, antalarmin and CP154526, resulted $IC_{50}$ values of $414.1{\pm}5.5$ and $290.7{\pm}1.9nM$, respectively. Similar results were presented with frozen HEK293a16/hCRF1 cells. Finally, our HEK293a16/hCRF1 cells with the aequorin based cellular functional assay can be a model system for the development of functional cosmetics and modulators that can have a clinical efficacy on hair re-growth.

Damage Evaluation of Track Components for Sleeper Floating Track System in Urban Transit (도시철도 침목플로팅궤도 궤도구성품의 손상평가)

  • Choi, Jung-Youl;Kim, Hak-Seon;Han, Kyung-Sung;Jang, Cheol-Ju;Chung, Jee-Seung
    • The Journal of the Convergence on Culture Technology
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    • v.5 no.4
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    • pp.387-394
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    • 2019
  • In this study, in order to evaluate the damage and deterioration of the track components of sleeper floating track (STEDEF), the field samples(specimens) were taken from the serviced line over 20 years old, and the track components were visually inspected, and investigated by laboratory tests and finite element analysis. As a result of visual inspection, the damage of the rail pad and fastener was slight, but the rubber boot was worn and torn at the edges of bottom. The resilience pads were clearly examined for thickness reduction and fatigue hardening layer. As a result of spring stiffness test of rail pad and resilience pad, the deterioration of rail pad was insignificant, but the deterioration of resilience pad exceeded design standard value. Therefore resilience pad was directly affected by train passing tonnage. As a result of comparing the deterioration state of the field sample and the numerical analysis result, the stress and displacement concentration position of the finite element model and the damage position of the field sample were coincident.

Determining Kinetic Parameters and Stabilization Efficiency of Heavy Metals with Various Chemical Amendment (중금속 안정화제의 반응 매개변수 결정 및 중금속 안정화 효율성 평가)

  • Oh, Se-Jin;Kim, Sung-Chul;Kim, Tae-Hee;Yeon, Kyu-Hun;Lee, Jin-Soo;Yang, Jae-E.
    • Korean Journal of Soil Science and Fertilizer
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    • v.44 no.6
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    • pp.1063-1070
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    • 2011
  • In this study, total of 5 different chemical amendments were evaluated for determining kinetic parameters and stabilization efficiency of heavy metals in aqueous phase. Standard solution of Cd and Pb ($100mg\;L^{-1}$) was mixed with various ratio of amendments (1, 3, 5, 10%) and heavy metal stabilization efficiency was monitored for 24hrs. All examined amendments showed over 90% of removal efficiency for both Cd and Pb except zerovalent iron (ZVI) for Cd (43-63%). Based on result of heavy metal stabilization efficiency, it was ordered as $CaCO_3$ > Dolomite > Zeolite > Steel slag > ZVI for both Cd and Pb in aqueous phase. For kinetic study, first order kinetic model was adapted to calculate kinetic parameters. In terms of reaction rate constants (k), zeolite showed the fastest reaction rate (k value from 0.4882 for 1% to 2.0105 for 10%) for Cd and ZVI (k value from 0.2304 for 1% to 0.5575 for 10%) for Pb. Considering reaction rate constant and half life for heavy metal stabilization, it was ordered as Zeolite > $CaCO_3$ > Dolomite > Steel slag > ZVI for Cd and $CaCO_3$ > Dolomite > Steel slag > Zeolite > ZVI for Pb. Overall result in this study can be interpreted that lime containing materials are more beneficial to remove heavy metals with high efficiency and less time consuming than absorbent materials.

A Study on Characteristics and Modeling of CMV by Grounding Methods of Transformer for ESS (ESS용 변압기의 접지방식에 의한 CMV 모델링 및 특성에 관한 연구)

  • Choi, Sung-Moon;Kim, Seung-Ho;Kim, Mi-Young;Rho, Dae-Seok
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.22 no.4
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    • pp.587-593
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    • 2021
  • Since 2017, a total of 29 fire accidents have occurred in energy storage systems (ESSs) as of June 2020. The common mode voltage (CMV) is one of the electrical hazards that is assumed to be a cause of those fire accidents. Several cases of CMV that violate the allowable insulation level of a battery section are being reported in actual ESS operation sites with △-Y winding connections. Thus, this paper evaluates the characteristics of CMV. An ESS site was modeled with an AC grid, PCS, and battery sections using PSCAD/EMTDC software. As a result of a simulation based on the proposed model, it was confirmed that characteristics of CMV vary significantly and are similar to actual measurements, depending on the grounding method of the internal transformer for PCS. The insulation level of the battery section may be severely degraded as the value of CMV exceeds the rated voltage in case of a grounding connection. It was found that the value of CMV dramatically declines when the internal transformer for PCS is operated as non-grounding connection, so it meets the standard insulation level.

A Study on The Influence Factors of Self-Efficacy, Job Performance, and Job Satisfaction of University Hospital Nurses (대학병원간호사의 자기효능감, 업무수행능력이 직무만족도에 미치는 영향요인)

  • Kim, Mi-Young;Lee, Hye-Kyung
    • Journal of the Korean Applied Science and Technology
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    • v.36 no.3
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    • pp.726-736
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    • 2019
  • The purpose of this study is to investigate the effect of University hospital nurses' self-efficacy and job performance on job satisfaction. The subjects of this study were 130 nurses working at a university hospital in C city and collected data using structured questionnaires. The collected data were analyzed using mean, standard deviation, t-test, ANOVA, Pearson's correlation and multiple regression analysis using spss 25.0. The results showed that the self-efficacy was 3.24 points for the average score, 2.74 points for the job performance, and 3.10 points for the job satisfaction. Self-efficacy, job performance, and job satisfaction were statistically correlated. The factors affecting job satisfaction were self-efficacy (${\beta}=.39$, p<.001), age at 30~34 years (${\beta}=-.27$, p=.001), Operating Room(${\beta}=-.17$, p=.029), Medical ward (${\beta}=-.17$, p=.025) and unmarried (${\beta}=-.20$, p=.012) and the explanatory power of the model was 30.4%. Based on the results of this study, it is necessary to develop a program to improve the job satisfaction considering the self-efficacy, age, working department of hospital nurse.

A Study on Machine Learning-Based Real-Time Automated Measurement Data Analysis Techniques (머신러닝 기반의 실시간 자동화계측 데이터 분석 기법 연구)

  • Jung-Youl Choi;Jae-Min Han;Dae-Hui Ahn;Jee-Seung Chung;Jung-Ho Kim;Sung-Jin Lee
    • The Journal of the Convergence on Culture Technology
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    • v.9 no.1
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    • pp.685-690
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    • 2023
  • It was analyzed that the volume of deep excavation works adjacent to existing underground structures is increasing according to the population growth and density of cities. Currently, many underground structures and tracks are damaged by external factors, and the cause is analyzed based on the measurement results in the tunnel, and measurements are being made for post-processing, not for prevention. The purpose of this study is to analyze the effect on the deformation of the structure due to the excavation work adjacent to the urban railway track in use. In addition, the safety of structures is evaluated through machine learning techniques for displacement of structures before damage and destruction of underground structures and tracks due to external factors. As a result of the analysis, it was analyzed that the model suitable for predicting the structure management standard value time in the analyzed dataset was a polynomial regression machine. Since it may be limited to the data applied in this study, future research is needed to increase the diversity of structural conditions and the amount of data.

The Prediction of DEA based Efficiency Rating for Venture Business Using Multi-class SVM (다분류 SVM을 이용한 DEA기반 벤처기업 효율성등급 예측모형)

  • Park, Ji-Young;Hong, Tae-Ho
    • Asia pacific journal of information systems
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    • v.19 no.2
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    • pp.139-155
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    • 2009
  • For the last few decades, many studies have tried to explore and unveil venture companies' success factors and unique features in order to identify the sources of such companies' competitive advantages over their rivals. Such venture companies have shown tendency to give high returns for investors generally making the best use of information technology. For this reason, many venture companies are keen on attracting avid investors' attention. Investors generally make their investment decisions by carefully examining the evaluation criteria of the alternatives. To them, credit rating information provided by international rating agencies, such as Standard and Poor's, Moody's and Fitch is crucial source as to such pivotal concerns as companies stability, growth, and risk status. But these types of information are generated only for the companies issuing corporate bonds, not venture companies. Therefore, this study proposes a method for evaluating venture businesses by presenting our recent empirical results using financial data of Korean venture companies listed on KOSDAQ in Korea exchange. In addition, this paper used multi-class SVM for the prediction of DEA-based efficiency rating for venture businesses, which was derived from our proposed method. Our approach sheds light on ways to locate efficient companies generating high level of profits. Above all, in determining effective ways to evaluate a venture firm's efficiency, it is important to understand the major contributing factors of such efficiency. Therefore, this paper is constructed on the basis of following two ideas to classify which companies are more efficient venture companies: i) making DEA based multi-class rating for sample companies and ii) developing multi-class SVM-based efficiency prediction model for classifying all companies. First, the Data Envelopment Analysis(DEA) is a non-parametric multiple input-output efficiency technique that measures the relative efficiency of decision making units(DMUs) using a linear programming based model. It is non-parametric because it requires no assumption on the shape or parameters of the underlying production function. DEA has been already widely applied for evaluating the relative efficiency of DMUs. Recently, a number of DEA based studies have evaluated the efficiency of various types of companies, such as internet companies and venture companies. It has been also applied to corporate credit ratings. In this study we utilized DEA for sorting venture companies by efficiency based ratings. The Support Vector Machine(SVM), on the other hand, is a popular technique for solving data classification problems. In this paper, we employed SVM to classify the efficiency ratings in IT venture companies according to the results of DEA. The SVM method was first developed by Vapnik (1995). As one of many machine learning techniques, SVM is based on a statistical theory. Thus far, the method has shown good performances especially in generalizing capacity in classification tasks, resulting in numerous applications in many areas of business, SVM is basically the algorithm that finds the maximum margin hyperplane, which is the maximum separation between classes. According to this method, support vectors are the closest to the maximum margin hyperplane. If it is impossible to classify, we can use the kernel function. In the case of nonlinear class boundaries, we can transform the inputs into a high-dimensional feature space, This is the original input space and is mapped into a high-dimensional dot-product space. Many studies applied SVM to the prediction of bankruptcy, the forecast a financial time series, and the problem of estimating credit rating, In this study we employed SVM for developing data mining-based efficiency prediction model. We used the Gaussian radial function as a kernel function of SVM. In multi-class SVM, we adopted one-against-one approach between binary classification method and two all-together methods, proposed by Weston and Watkins(1999) and Crammer and Singer(2000), respectively. In this research, we used corporate information of 154 companies listed on KOSDAQ market in Korea exchange. We obtained companies' financial information of 2005 from the KIS(Korea Information Service, Inc.). Using this data, we made multi-class rating with DEA efficiency and built multi-class prediction model based data mining. Among three manners of multi-classification, the hit ratio of the Weston and Watkins method is the best in the test data set. In multi classification problems as efficiency ratings of venture business, it is very useful for investors to know the class with errors, one class difference, when it is difficult to find out the accurate class in the actual market. So we presented accuracy results within 1-class errors, and the Weston and Watkins method showed 85.7% accuracy in our test samples. We conclude that the DEA based multi-class approach in venture business generates more information than the binary classification problem, notwithstanding its efficiency level. We believe this model can help investors in decision making as it provides a reliably tool to evaluate venture companies in the financial domain. For the future research, we perceive the need to enhance such areas as the variable selection process, the parameter selection of kernel function, the generalization, and the sample size of multi-class.