• Transactions of the Korean Society of Mechanical Engineers A
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• 제33권12호
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• pp.1449-1454
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• 2009

The performance variation of a multibody system is affected by a variation of various design variables of the system. And the effects of design variable variations on the performance variation must be considered in design of a multibody system. Accordingly, a variation analysis of a multibody system needs to be conducted in design of a multibody system. For a variation analysis of a performance, population mean and variance which are called statistical parameters of design variables are needed. However, an evaluation of statistical parameters of design variables is impossible in many practical cases. Therefore, an estimation of statistical parameters of the performance based on sample mean and variance which are called statistic of design variables is needed. In this paper, the variation analysis method for a multibody system based on design variable samples was proposed. And, using the proposed method, a variation analysis of the vehicle ride comfort based on sample statistic of design variables was conducted.

• International Journal of Concrete Structures and Materials
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• 제7권3호
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• pp.175-182
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• 2013

A damage-based approach for the performance-based seismic assessment of reinforced concrete frame structures is proposed. A new methodology for structural damage assessment is developed that utilizes response information at the material level in each section fiber. The concept of the damage evolution is analyzed at the section level and the computed damage is calibrated with observed experimental data. The material level damage parameter is combined at the element, story and structural level through the use of weighting factors. The damage model is used to compare the performance of two typical 12-story frames that have been designed for different seismic requirements. A series of nonlinear time history analyses is carried out to extract demand measures which are then expressed as damage indices using the proposed model. A probabilistic approach is finally used to quantify the expected seismic performance of the building.

• International Journal of Control, Automation, and Systems
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• 제5권5호
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• pp.584-593
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• 2007

BACnet is a standard data communication protocol especially designed for building automation and control networks. BACnet uses the Master-Slave/Token-Passing (MS/TP) protocol as one of its field-level networks. In this study, the performance of the BACnet MS/TP protocol is evaluated using an experimental model. The network performance is investigated and evaluated in terms of token rotation time and round trip time. The experimental results show that the performance of the MS/TP network is heavily influenced by the network traffic load, the assignment of MS/TP node address and the network configuration parameter called $N_{max_info-frames}$. Based on the experimental results, simple practical designing guidelines for BACnet MS/TP network systems are also proposed.

• 유체기계공업학회:학술대회논문집
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• 유체기계공업학회 2002년도 유체기계 연구개발 발표회 논문집
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• pp.408-416
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• 2002

Hydraulic performance of the pump with an inducer was predicted by 3-D Navier-stokes calculation. The evaluated pump was the single-stage centrifugal pump with a separated inducer to pressurize fuel (LCH4) in Turbo-pump system with a specific speed (Ns) of approximately 0.3[rad/s, m3/s, J/kg] and a suction specific speed(s) of 15[rad/s, m3/s, J/kg]. That conventional pump was designed with the combination of 1-D theory and empirical correlation. In this study, preliminary design to select key parameters such as inlet flow coefficient was reviewed by investigating sets of the known design methods to achieve appropriate suction performance, and the performance of newly designed inducer and impeller was compared with the old one, using CFD method. The numerical results showed that the hydraulic efficiency of the new pump was predicted $5.5\%$ higher than that of the conventional one, through design parameter re-selection, configuration improvement and blade loading control

• Journal of the Korea Convergence Society
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• 제11권10호
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• pp.219-224
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• 2020

Industrial mixers to homogeneously blend particulate materials have been developed and widely used in various industries. However, most industrial mixers have at most two-degree-of-freedom for the operation, which limits the range of operation parameter selection for optimal blending. This paper proposes a multi-degree-of-freedom robotic mixer designed by converging a conventional drum blender and a robotic manipulator and evaluated its performance in a virtual operating environment. Discrete element simulations were conducted for mixing performance evaluation. The numerical results showed that the proposed mixer design exhibits a better mixing performance than conventional ones.

• Proceedings of the Korean Information Science Society Conference
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• 한국정보과학회 2006년도 가을 학술발표논문집 Vol.33 No.2 (B)
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• pp.233-237
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• 2006

This study proposes an innovative measure for evaluating the performance of text clustering. In using K-means algorithm and Kohonen Networks for text clustering, the number clusters is fixed initially by configuring it as their parameter, while in using single pass algorithm for text clustering, the number of clusters is not predictable. Using labeled documents, the result of text clustering using K-means algorithm or Kohonen Network is able to be evaluated by setting the number of clusters as the number of the given target categories, mapping each cluster to a target category, and using the evaluation measures of text. But in using single pass algorithm, if the number of clusters is different from the number of target categories, such measures are useless for evaluating the result of text clustering. This study proposes an evaluation measure of text clustering based on intra-cluster similarity and inter-cluster similarity, what is called CI (Clustering Index) in this article.

• Proceedings of the KIEE Conference
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• 대한전기학회 2001년도 합동 추계학술대회 논문집 정보 및 제어부문
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• pp.184-186
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• 2001

This paper describes a method of human sensibility evaluation for pleasant and unpleasant environments. Conditions of the environment are room temperature and humidity. Changing the conditions, 10-channel EEG signals for 4 subjects are collected. Linear predictor coefficients of the recorded EEGs are extracted as the feature parameter of human sensibility. A neural network-based human sensibility estimation algorithm is developed. The developed algorithm showed good performance in the pleasantness evaluation. The neural network output produced accurate states of pleasantness sensibility. Subject-independent test showed similar results with subject-dependent test.

• Journal of information and communication convergence engineering
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• 제19권4호
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• pp.241-247
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• 2021

Particulate matter has emerged as a serious global problem, necessitating highly reliable information on the matter. Therefore, various algorithms have been used in studies to predict particulate matter. In this study, we compared the prediction performance of neural network models that have been actively studied for particulate matter prediction. Among the neural network algorithms, a deep neural network (DNN), a recurrent neural network, and long short-term memory were used to design the optimal prediction model using a hyper-parameter search. In the comparative analysis of the prediction performance of each model, the DNN model showed a lower root mean square error (RMSE) than the other algorithms in the performance comparison using the RMSE and the level of accuracy as metrics for evaluation. The stability of the recurrent neural network was slightly lower than that of the other algorithms, although the accuracy was higher.

• Proceedings of the KIEE Conference
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• 대한전기학회 2004년도 학술대회 논문집 정보 및 제어부문
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• pp.544-546
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• 2004

This paper designs and evaluates a complementary filter for fusion of inertial sensor signals. Specifically, the designed filter is applied to inverted pendulum control where the pendulum's angle information is obtained from low-cost tilt and gyroscope sensors instead of an optical encoder. The complementary filter under consideration is a conventional one which consists of low- and high-pass filters. However, to improve the performance of the filter on the gyroscope, we use an integrator in the filter's outer loop. Frequency responses are obtained with both tilt and gyroscope sensors. Based on the frequency response results, we determine appropriate parameter values for the filter. The performance of the designed complementary filter is evaluated by applying the filter to inverted pendulum control. Experiments show that the performance of the designed filter is comparable to that of an optical encoder and low-cost inertial sensors can be used for inverted pendulum control with the heir of sensor fusion.

• Proceedings of the Korea Concrete Institute Conference
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• 한국콘크리트학회 2008년도 추계 학술발표회 제20권2호
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• pp.821-824
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• 2008

This paper presents a systematic approach for estimating material performance of concrete mixture design based on satisfaction curves developed from statistical evaluation of existing or newly obtained material property related data. In performance based material design (PBMD) method, concrete material used for construction of a structure is designed considering a structure's specified performance requirements based on its usage and characteristics such as environmental conditions, structure types, expected design life, etc.Satisfaction curves express the probabilities that one component of substrates (i.e., aggregate size, cement content, etc) of concrete mixture will sustain different criterion value for a given concrete mixture design. This study presents a statistical analysis method for setting up concrete material parameter versus concrete criterion relationships in the form of satisfaction curves and for estimating confidence bounds on these satisfaction curves. This paper also presents an analysis method to combine multiple satisfaction curves to form one unique satisfaction curve that can relate the performance of concrete to a single evaluating value. Based on several evaluated mixture design examples for various material properties, the validity of the proposed method is discussed in detail.