• 제어로봇시스템학회논문지
• /
• 제19권12호
• /
• pp.1081-1088
• /
• 2013

Hyperspectral cameras acquire reflectance values at many different wavelength bands. Dimensions tend to increase because spectral information is stored in each pixel. Several attempts have been made to reduce dimensional problems such as the feature selection using Adaboost and dimension reduction using the Simulated Annealing technique. We propose a novel material detection method that consists of four steps: feature band selection, feature extraction, SVM (Support Vector Machine) learning, and target and specific region detection. It is a combination of the band ratio method and Simulated Annealing algorithm based on detection rate. The experimental results validate the effectiveness of the proposed feature selection and band ratio method.

• International Journal of Concrete Structures and Materials
• /
• 제6권2호
• /
• pp.87-100
• /
• 2012

The process of selecting a repair material is a typical one of multi-criteria decision-making (MCDM) problems. In this study Analytical Hierarch Process was applied to solve this MCDM problem. Many factors affecting a process to select an optimal repair material can be classified into quantitative and qualitative requirements and this study handled only quantitative items. Quantitative requirements in the optimal selection model for repair material were divided into two parts, namely, the required chemical performance and the required physical performance. The former is composed of alkali-resistance, chloride permeability and electrical resistivity. The latter is composed of compressive strength, tensile strength, adhesive strength, drying shrinkage, elasticity and thermal expansion. The result of the study shows that this method is the useful and rational engineering approach in the problem concerning the selection of one out of many candidate repair materials even if this study was limited to repair material only for chloride-deteriorated concrete.

• 한국콘크리트학회:학술대회논문집
• /
• 한국콘크리트학회 2004년도 춘계 학술발표회 제16권1호
• /
• pp.664-667
• /
• 2004

It may have to establish the definite standard for performance evaluation basis about cementitious waterproofing material in job site that applied the method of construction formed cement waterproof course on concrete surface In present paper shows the effective selection method of waterproof layer of optimum thickness for economic performance as evaluating of the need thickness on waterproof property of penetrating waterproofing material.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2009년도 하계학술대회 논문집
• /
• pp.401-401
• /
• 2009

Recently, demands for the development of compact, lightweight power supplies with higher power density and higher efficiency have been increased. Since Piezoelectric Transformer (PT) was emerged in device and material industry, it has been suggested as a viable alternative to the magnetic transformer in some applications. PT has some advantages such as low profile and mechanical energy transfer with little electromagnetic interface (EMI). Also, PT can provide high voltage stepping ratio with good isolation and requires no copper windings saving copper usage especially for large voltage conversion differences. Conventional control of PT converter has mainly two-way. One is the pulse frequency modulation (PFM) control method and the other is the pulse width modulation (PWM) control with frequency fixed method. It is known that the maximum PT efficiency can be obtained when it operates near the resonant frequency of the PT. And, also PT's resonant frequency moves according to the load condition. Therefore, selection of PT converter control method is very difficult. This paper analyzes general piezo-electric converter modeling and proposes a guide-line to selection of control method and stabilization control.

• 대한인간공학회지
• /
• 제36권4호
• /
• pp.325-341
• /
• 2017

Objective: The purpose of this study is to suggest the guidelines of operation phases to minimize injuries and musculoskeletal disorders in manual material handling (MMH) tasks through literature reviews. The guidelines are presented as the preparing phase, lifting phase, carrying phase, and lowering phase. Also, we summarized the non-numerical general guidelines for MMH tasks. Background: Manual material handling is still a main cause to musculoskeletal disorders. Method: Procedures of a literature review are classified into database selection, keyword search, title review, abstract review related to literature selection, guideline review and arrangement. A total 48 papers and books were analyzed in detail by title and abstract reviews. Results: In the preparing phase, we suggested the basic conditions in MMH, preparing procedure, clothing and protective equipment, and education. In the lifting and carrying phases, we recommended maximal acceptable weight by frequency and body posture. In the lowering phase, we suggested the lowest weight and safety body postures. Finally, we recommended general guidelines and guideline items for MMH. General guidelines are presented to suggest worker selection, technical education, and work design parts. Conclusion: We suggested the guidelines on the four operation phases of MMH tasks such as preparing, lifting, carrying, and lowering phases. Application: The findings of this study can be utilized as guidelines for proactive recommendations according to workers in MMH tasks.

• 한국농공학회논문집
• /
• 제50권1호
• /
• pp.95-106
• /
• 2008

Eco-friendly material and implementation methods have become important along with the existing standardized maintenance concept for the irrigation and flood control. However, the intrinsic function of the hydraulic structure is water supply and disaster prevention. Therefore, the material and work methods should be considered both eco-friendliness, durability and safety which are prerequisite elements to maintain the engineering function. In this study eco-friendly material and work methods would be classified into the vegetation based system, eco-friendly concrete system and stone-material system according to the characteristics of material. The quality standard for durability followed KS specification and related regulations. The quality standard for safety and eco-friendliness was set after literature review, and the database was developed using the standard. The structure applicable to onsite - the eco-friendly material and work method were classified based on the function and material of the hydraulic structure. Finally, database has been established for convenient management and selection of the proper material and work method. The eco-friendly material and work method could be searched easily for the convenience of the users, and the web-based data system has been developed for continuous registration of the material and work methods to be developed in the future.

• 한국공작기계학회논문집
• /
• 제18권1호
• /
• pp.59-67
• /
• 2009

The purpose of this study is to provide a decision support to select an appropriate layered manufacturing(LM) machine that suits the application of a part. Selection factors include concept model, form/fit/functional model, pattern model far molding, material property, build time and part cost that greatly affect the performance of LM machines. However, the selection of a LM is not an easy decision because they are uncertain and vague. For this reason, the aim of this research is to propose hybrid multiple attribute decision making approaches to effectively evaluate LM machines. In addition, because subjective considerations are relevant to selection decision, a fuzzy logic approach is adopted. The proposed selection procedure consists of several steps. First, we identify LM machines that the users consider After constructing the evaluation criteria, we calculate the weights of the criteria by applying the fuzzy Analytic Hierarchy Process(AHP) method. Finally, we construct the fuzzy Technique of Order Preference by Similarity to Ideal Solution(TOPSIS) method to achieve the ranking order of all machines providing the decision information for the selection of LM machines.

• 한국기계가공학회지
• /
• 제7권3호
• /
• pp.87-95
• /
• 2008

The purpose of this study is to provide a decision support to select an appropriate rapid prototyping(RP) machine that suits the application of a part. Selection factors include concept model, form/fit/functional model, pattern model for molding, material property, build time and part cost that greatly affect the performance of RP machines. However, the selection of a RP is not an easy decision because they are uncertain and vague. For this reason, the aim of this research is to propose hybrid multiple attribute decision making approaches to effectively evaluate RP machines. In addition, because subjective considerations are relevant to selection decision, a fuzzy logic approach is adopted. The proposed selection procedure consists of several steps. First, we identify RP machines that the users consider. After constructing the evaluation criteria, we calculate the weights of the criteria by applying the fuzzy Analytic Hierarchy Process(AHP) method. Finally, we construct the fuzzy Technique of Order Preference by Similarity to Ideal Solution(TOPSIS) method to achieve the ranking order of all machines providing the decision information for the selection of RP machines.

• 한국지능정보시스템학회:학술대회논문집
• /
• 한국지능정보시스템학회 2005년도 춘계학술대회
• /
• pp.302-305
• /
• 2005

To comply to demand for a development requirement of aircraft design part, the expert system builds up standard knowledge-base based on presently maintained expert knowledge and experience in aircraft structure material selection. It also builds up database based on aircraft design open data, and standard calculation module used for present design and analysis method. This system is developed using Visual Basic language. The expert system standardize aircraft structure material selection and can be applied to all type of elementary stage of aircraft structure design. It is working on Windows, which has a friendly interface and is convenient for debugging, maintenance and transplanting. Explanation of the structure and the function of the system was given in this paper.

• 한국안전학회지
• /
• 제12권2호
• /
• pp.17-21
• /
• 1997

The fatigue crack propagation rate has so far been measured by the effective stress intensity factor range Δ K/sub eff/. But no research has been done to study how much the crack opening ratio influences the expectation of the fatigue crack propagation. Therefore, this paper evaluates of the crack opening ratio on the fatigue crack propagation life by using the method of parameter sensitivity study. Summarizing the result ; ( 1 ) When the crack opening ratio U' is high, the effect of U' gets larger than any other except for the material factor m. But when U' is low, the effect is also diminished. Therefore, the selection of the lowest value possible is desirable in the evaluation of life. (2) When the value of the material factor m is high, the effect of crack opening ratio U' is increased, at the same time the effect of the other parameters also increased wholly. The effect of material factor m itself on life is high, but in case the material factor m is high, that the effect of each parameter on life get higher is unique. In designing, better attention to the material selection should be drawn. (3) In case the stress ratio R gets smaller, the effect of crack opening ratio U' is unchangeable. But the effect of R itself remarkably decreases, and the effect of material factor m somewhat decreases.