Earticle

This study proposes an optimal heat sink fin design for robot actuator housings under high-pressure die-casting (HPDC) constraints. Three fin geometries — straight, wave, and pin types — were evaluated using steady-state thermal analysis based on Newton's Law of Cooling. Wave-type fins achieved greater heat dissipation area than straight-type fins at equal thickness, enabling approximately 0.4 mm thinner fins and 9.4 g weight reduction under equal-area conditions. To further refine the wave geometry under manufacturability constraints, a Box-Behnken design with 26 cases was conducted across two fin-count groups (n=5, n=6). Multiple regression analysis identified fin thickness, fin count, and wavelength as factors with statistically meaningful effects on filling temperature, while fin count was the dominant factor governing thermal performance (=−2.83 °C, p<0.001). The results indicate that geometry-only optimization is insufficient to secure mass-production margin within current process conditions, and a combined adjustment of process parameters (melt superheat, gate area, injection velocity) is required.

Stainless steel sheets are widely used as the structure material for the railroad cars and the commercial vehicles. These kinds structures used stainless steel sheets are commonly fabricated by using the gas welding. For fatigue design of gas welded joints such as fillet and plug and ring type joint, it is important to obtain optimum design parameter information on gas welded joints. In this paper, analysis approach for fatigue test using experimental design are evaluated optimum factor in gas welded joint type and geometrical parameters of materials. Using these results, that factors applied to fundamental information for fatigue design.

The purpose of this paper is to propose an analysis method to assess the influence of Performance Based Logistics(PBL) and to apply the PBL to the Korean Utility Helicopter(KUH) Engine. It is necessary to develop a simulation model that represents the operation and maintenance process of the KUH engine to achieve the target operational availability(Ao) and to minimize the life cycle cost. A simulation model is used to assess the average readiness and to estimate the amount of operation and maintenance cost of alternatives. This paper also uses the experimental design technique to sample the input scenarios and the regression tree technique to analyze the influence of 28 logistics factors. Some of the factors are the reliability value (Mean Time Between Failure), the number of spare parts, the repair time of the 9 modules, and the administrative and transportation delay time which is commonly applied to the 9 modules. The combined technique enables us to identify the logistics factors that affect the operational availability and the life cycle cost. The proposed methodology can be applied to the Performance Based Logistics of other weapon systems provided that some factors are modified to fit the situation.

A computer code was developed to simulate both the thermal stresses introduced during the post-filling stage and the in-plane deformation after ejection process by finite element method based on the plane stress theory. The computer simulation was applied to the mold design of a 2 inch light guide plate (LGP) for thin film transistor (TFT)-liquid crystal displays (LCD). With injection molding experiments based on the design of experiments (DOE) technique, the influences of the processing conditions in injection molding on brightness and uniformity of the LGP were investigated, and the optimal processing parameters were selected to increase the brightness and uniformity. The verification experiment showed that the brightness and uniformity of the LGP were increased dramatically under the selected optimal processing conditions.

Wheel loader is one of the construction machinery capable of variety of tasks and the demand on functional diversity and structural reliability is growing. As a study on the optimal shape design of front axle for wheel loader through the design of experiments, this paper assessed the design parameters affecting the maximum stress. As a result, a value of 126.77 MPa of minimum stress was obtained, and optimal factors showed the values of w = 100.0 mm, ${\theta}=40^{\circ}$ and R = 118 mm. It showed an accuracy of 98.7% compared with the structural analysis.

In this research. we have proposed a new technique to determine .the combination of design parameters for the process design of a hot forged product using artificial neural network(ANN) and statistical design of experiments(DOE). The investigated problem involves the adequate selection of the aspect ratio of billet, the ram velocity and the friction factor as design parameters. An optimal billet satisfying the forming limitation, die filling, load and energy as well as more uniform distribution of effective strain, is determined by applying the ability of artificial neural network and considering the analysis of mean and variation on the functional requirement. This methodology will be helpful in designing and controlling parameters on the shop floor which would yield the best design solution.

Optimal mount position of a front pillar trim considering heat resistant characteristics can be determined by two methods. One is conventional approximate optimization method which uses the statistical design of experiments (DOE) and response surface method (RSM). Generally, approximated optimum results are obtained through the iterative process by a trial and error. The quality of results depends seriously on the factors and levels assigned by a designer. The other is a methodology derived from previous work by the authors, which is called sequential design of experiments (SDOE), to reduce a trial and error procedure and to find an appropriate condition for using artificial neural network (ANN) systematically. An appropriate condition is determined from the iterative process based on the analysis of means. With this new technique and ANN, it is possible to find an optimum design accurately and efficiently.

Spindle units of machine tool are very important part in the manufacturing area. Recently high speed machining has become the main issue of metal cutting. To develop high speed machine tools, a lot of studies have been carried out for high speed spindle. Due to increase of the rotational speed of the spindle, there has been renewal of interest in vibration of spindle. This paper concerns the improvement of spindle design using design of experiments. To improve the design of critical speed and weight of spindle, the experiments using central composite method have been carried out. The targets are critical speed and weight of spindle. For optimization of critical speed and weight and optimization of only critical speed by operation of all area search through response optimizer, the result of analysis has improved design of each factor. Finite element analyses are performed by using the commercial codes ARMD, CATIA V5 and ANSYS workbench. From the results, it has been shown that the proposed method is effective for modification of spindle design to improve critical speed and weight.

Since human listening is very sensitive when the sound hit him, the subjective index of sound quality is required. Therefore, at each situation of sound evaluation its composed with the sound quality factor. But, when substituting the level of one frequency band we could not see the tendency of substitution at whole frequency band during the sound quality evaluation. In this study a design of experiment is used. The frequency domain is divided into an equally 12 parts and each level of domain whether is given increase or decrease due to the change of frequency band based on 'sharp' and 'annoy' of the sound quality is analyzed. By using the design of experiment the number of test is reduce very effectively by the number of experiment and each band the main effect will be as a solution. The case of sound quality for 'sharp' and 'annoy' at each band, the change of band (increase or decrease of sound pressure or keep maintain) which will be the most effects on the characteristics of sound quality can be identify and this will be able to us to select the objective frequency band. Through these obtained results the physical changes of level at arbitrary frequency domain sensitivity can be adapted.

This paper has studied to obtain the grinding characteristics and optimal grinding conditions of ceramic materials in the grinding with diamond wheel by design of experiments. The load on wheel by varying the feed rate was related with the surface roughness due to the minute destruction phenomenon of grains for the $Si_3\;N_4\;and\;ZrO_2$. The depth of cut is related with the surface roughness because the grinding is carried out by grain shedding process due to the brittle fracture phenomenon for the $A1_2\;O_3$. The major factors affecting the surface roughness and the optimum grinding conditions were obtained with minimum experiments using design of experiments.

High-speed machining is one of the most effective technologies to improve productivity. Because of the high speed and high feed rate, high-speed machining can give great advantages for the machining of dies and molds. This paper describes on the improvement of machining accuracy in high-speed machining. Depth of cut, feed rate and spindle revolution are control factors. The effect of the control factors on machining accuracy is investigated using two-way factorial design.

High speed machining(HSM) technique is widely used in the appliance, automobile part and mold industries, because it has many advantages such as good quality, low cost and rapid machining time. But it also has problems such as tool breakage, smooth tool path, and so on. In particular, small size end mill is easy to break, so it must be changed before interrupting operation. Generally, the tool life of small size end mill is affected by the milling conditions whose selected parameters are spindle speed, feedrate, and width of cut. The experiments were carried out by full factorial design of experiments using an orthogonal array. This paper shows optimal combination and mathematical model for tool life, Therefore, the analysis of variance(ANOVA) is employed to analyze the main effects and the interactions of these milling parameters and the second-order polynomial regression model with three independent variables is estimated to predict tool life by multiple regression analysis.

As a safety device, a rupture disc are used to control pressure to minimize the explosion risk once the internal pressure of high pressure equipment exceeds a critical level. In this paper, optimization method was developed to secure optimal design of domed Rupture disks. The parameter analysis was performed through design of experiment to parameter of Rupture disk made of AISI 316.The Diameter, Thickness and Hight of Rupture disk were selected as design parameters for design parameter analysis. The results of parameter analysis revealed that the Diameter, thickness and hight were burst pressure-sensitive design parameters. Based on the valid performance factors, a regression equation to predict its performance was deducted and using the equation, an optimal design. And a sample model was fabricated, followed by burst pressure testing, after optimal design and analytical verification. In this research, it is verified that the optimal design method and the credibility of the analysis of this study is deemed very high. Furthermore, utilizing this mechanism would inspect the effect of the design parameter performance and increase the credibility and efficiency of a design.

본 연구에서는 해양플랜트의 플로트오버 설치작업을 위해 개발된 능동형 갑판 지지 프레임 (Deck support frame, DSF)의 구조설계에 대해 다양한 실험계획법을 이용한 민감도해석의 비교연구를 수행하였다. 능동형 DSF의 주요 구조부재의 두께 치수 변수는 설계인자로 고려하였고, 응답치는 중량과 강도성능으로부터 선정하였다. 민감도해석의 비교연구에 사용한 실험계획법은 직교배열설계법, Box-Behnken 설계법 그리고 Latin hypercube 설계법이다. 실험계획법의 설계공간 탐색의 근사화 성능을 평가하기 위해 반응표면법을 각 실험계획법 별로 생성하여 근사화 정확도 특성을 검토하였다. 또한 최상설계안 의 결과로부터 실험계획법의 특성에 따른 수치계산 비용, 중량감소 효과 등과 같은 설계향상 효과를 비교하였다. 능동형 DSF의 구조설계에 대해 직교배열설계법이 가장 향상된 결과를 나타내었다.

The paper deals with comparative study on sensitivity analysis using various methods regarding to design of experiments for structure design of an active type DSF (Deck support frame) that was developed for float-over installation of offshore plant. The thickness sizing variables of structure member of the active type DSF were considered the design factors. The output responses were defined from the weight and the strength performances. Various methods such as orthogonal array design, Box-Behnken design, and Latin hypercube design were applied to the comparative study. In order to evaluate the approximation performance of the design space exploration according to the design of experiments, response surface method was generated for each design of experiment, and the accuracy characteristics of the approximation were reviewed. The design enhancement results such as numerical costs, weight minimization, etc. via the design of experiment methods were compared to the results of the best design. The orthogonal array design method represented the most improved results for the structure design of the active type DSF.

The MR fluid jet polishing process operates on the principle that the viscosity of MR fluid changes in response to a magnetic field. By applying a magnetic field during slurry injection, the fluid is consistently sprayed in a laminar, straight flow, with the nozzle diameter nearly matching the size of the injected fluid. This ensures stable, straight-line spraying, even when the injection height changes. The factors influencing material removal and surface roughness, which are indicators of the polishing rate, can be categorized into process parameters occurring during the polishing operation and the material properties of the workpiece. Due to the independent effects of numerous factors and the interactions between them, the polishing characteristics are highly complex, making it essential to understand the underlying polishing phenomena. To analyze the factors influencing the results, design of experiments (DOE) and regression analysis were applied. The results revealed that, in the MR fluid jet polishing process, the most significant factor affecting surface roughness is the feed speed, followed by injection pressure, and finally, the magnetic field.

Screws are the closest and most familiar mechanical elements of everyday life, and are generally used so widely that there is no machine without screws. Screws are used to make it easier to combine objects with objects, and are also used to transfer large forces from machines. The most influential factor in the coupling of these screws is the effective diameter. If the effective diameter is not accurate, the support cannot be finished or endured, leading to a major accident. The importance of these screws cannot be ignored, so in this study, the effective diameter was measured using the three-wire method, the screw micrometer method, and the projector method, and the one-way factor design method was applied to determine the exact method compared to the KS standard.

전기자동차용 구동모터로서 영구자석형 동기전동기가 주로 사용되고 있으며, 전기자동차에서 요구하는 다 양한 특성을 동시에 만족해야 되기 때문에 최적화에 대한 연구가 활발하게 진행되고 있다. 하지만 기존의 영구자 석형 동기전동기의 최적설계 방법은 실험횟수만큼의 기계적인 모델링, 유한요소해석이 필요하므로 매우 복잡하고 시간이 많이 소요된다. 본 논문에서는 자동화된 실험계획법과 유한요소해석을 바탕으로 영구자석형 동기전동기의 최적설계 방법을 연구하였다. 전동기의 형상최적화는 두 개의 메타모델링 기법과 두 개의 최적설계 알고리즘을 각 각 조합하여 수행된다. 첫째, 전동기의 평균토크는 목적함수로 설정되었고, 둘째, 역기전력의 고조파 왜곡, 효율, 토크리플은 제약조건으로 설정되었다. 자동화된 실험계획법에 의해 전동기의 유한요소해석은 쉽게 수행되며, 이 결과를 바탕으로 민감도 분석과 메타모델링이 진행되었다. 메타모델링은 기존에 주로 사용되는 Kriging 모델과 MLP(Multi-Layer Perceptron) 기법을 각각 이용하였고, 생성된 메타모델들은 전동기의 형상최적화를 위해 각각 유전알고리즘과 HMA(Hybrid Metaheuristic Algorithm) 알고리즘과 결합되었다. 본 연구에서는 최적화가 용이한 자동화된 설계 절차를 통해 다양한 메타모델링 기법과 최적 알고리즘을 검토할 수 있었으며, 결론적으로 MLP 기 법을 이용한 최적설계 결과는 Kriging 모델에 비해 더 우수한 평균토크 결과를 보여주었다.

As the traction motor for an electric vehicle requires various characteristics at the same time, research on the optimal design of the permanent magnet synchronous motor (PMSM) has been actively conducted. Because conventional optimal design of PMSM requires mechanical modeling and finite element analysis (FEA), the optimization procedure is complicated and time-consuming. To optimize PMSM easily and accurately, this study proposes an optimal design process based on automated design of experiments (DOE) and FEA. The shape optimization of PMSM is performed by applying two metamodeling techniques and two optimal algorithms, respectively. First, the average torque is set as the objective function, and second, THD of the back EMF, efficiency, and torque ripple are set as constraints. FEA-based analysis could be easily performed using automated DOE. Based on this, sensitivity analysis and metamodeling are performed. Metamodeling is accomplished using the previous Kriging and multi-layer perceptron (MLP) techniques, respectively. The generated metamodels are combined with GA and HMA(Hybrid Metaheuristic Algorithm) to perform PMSM shape optimization. In this study, various metamodeling techniques and optimal algorithms could be reviewed using an automated design procedure that is easy to optimize. In conclusion, the optimal design results using the MLP technique showed better average torque results than the Kriging model.

본 연구는 소비자들이 자신의 정체성에 따라 중소제과점에서의 가격민감도에 차이가 있는지와 희생 정신의 역할을 확인하는 것이 목적이다. 이를 위해 본 연구는 일반 소비자를 대상으로 총 3번의 실험 을 진행하였으며, 실험방식은 실험설문지를 온라인 및 모바일을 통해 무작위 배포하여 진행하였다. 실험 1은 일반 소비자들에게 프랜차이즈 베이커리와 로컬 베이커리에 대한 선호도 집단을 구분하여 10~30% 가격인상 수준에서의 각 집단별 가격민감도 차이를 비교하였다. 총 96명의 응답 내용을 분 석한 결과, 로컬 베이커리를 선호하는 소비자들이 프랜차이즈를 선호하는 소비자들보다 가격민감도가 낮았다. 실험 2는 소비자에게 소상공인 정체성과 프랜차이즈 정체성 프라이밍한 후 희생정신 및 로컬 베이커리에서의 가격민감도를 측정하였다. 총 107명의 응답자료를 분산분석한 결과, 소상공인 정체성 을 가진 소비자들이 프랜차이즈 정체성을 가진 소비자들에 비해 낮은 가격민감도를 보였고 그 심리적 매커니즘에 희생정신이 매개하고 있음을 확인하였다. 실험 3은 실험2를 발전시켜 구체적인 희생정신 의 역할을 규명하기 위해 각 소비자 정체성별로 희생정신을 프라이밍한 실험집단과 프라이밍하지 않 은 통제집단으로 나누어 2X2 집단간 설계 후 총 4집단의 가격민감도를 비교분석하였다. 총 188명의 응답자료를 분석한 결과, 소비자 정체성이 가격민감도에 미치는 영향에 희생정신이 상호작용 효과가 나타남을 확인하였다. 특히 프랜차이즈 정체성을 가진 소비자들에게 소상공인에 대한 희생정신을 주 입하였을 때 가격민감도가 크게 낮아졌다. 이는 마케팅 관점에서 로컬 베이커리와 프랜차이즈 가맹본부 및 가맹점에 각각 다음과 같은 시사점 을 제공한다. 로컬 베이커리 점포는 기존 고객들은 희생정신이 높기 때문에 이들을 위한 차별화된 서 비스를 제공하면서도 한편으로 가격민감도가 높은 신규 고객 창출을 위해 가격할인 정책이나 이벤트 행사를 실시에 주력할 필요가 있다. 반면, 프랜차이즈 가맹본부와 가맹점은 주 고객이 가격민감도가 높다는 점에 주목하여 전체 또는 개별적인 가격인상에 신중하여야 한다. 또한 가맹점의 경우에는 자 신도 로컬 베이커리와 다름없이 보호받아야 할 소상공인임을 소비자들에게 적극적으로 알려 희생정신 활성화를 통해 고객 이탈을 방지하는 노력을 할 필요가 있다.

The purpose of this study is to examine whether consumers have different price sensitivities in small bakeries according to their identity and the role of sacrifice. For this purpose, this study was conducted three experimental studies for general consumers, and the experimental method was distributed randomly through online and mobile experiment questionnaires. Experiment 1 compares the difference of price sensitivities of each group at 10 ~ 30% price increase level by dividing the preference group of franchise bakery and local bakery into general consumers. As a result of analyzing the responses of 96 respondents, consumers who prefer local bakery have lower price sensitivity than those who prefer franchise. Experiment 2 measures consumers' sacrifice spirit and price sensitivity in local bakery after prime identity and franchise identity priming. As a result of analyzing 107 respondents' data, it was found that consumers with small identity had lower price sensitivity than those with franchise identity and mediated the psychological mechanism. In Experiment 3, Experiment 2 was developed to clarify the role of specific sacrifice. In order to clarify the role of specific sacrifice, we divided the experimental group with the priming spirit and the non-priming control group according to each consumer identity. As a result of analyzing 188 respondents' data, it was confirmed that the effect of sacrificial mindset interacted with the effect of consumer identity on price sensitivity. Especially, the price sensitivity of consumers who have franchise identity is lowered when they inject sacrifice mindset for small business person. This provides the following implications to local bakery, franchisors and franchisees in terms of marketing. Local bakery stores need to concentrate on price reduction policies and event events to create new customers with high price sensitivity while providing existing customers with differentiated services because of their high sacrifice. On the other hand, franchisors and franchisees should be cautious about the overall or individual price increase, noting that the main customer is highly price sensitive. In addition, in the case of franchisee, it is necessary to actively show consumers that they are small business owners who should be protected like a local bakery, and try to prevent the departure of customers through activation of sacrifice.

본 연구는 대한민국 정부의 기술혁신형 국가연구개발사업 중 하나인 “지식경제기술혁신사 업”을 대상으로 R&D 성과창출 성공확률의 예측모형을 추정하고, 추정된 예측모형의 민감도 검토를 위한 실험설계분석을 실시한다. 분석 대상 R&D 주관기관 유형은 “대기업”, “중소기 업”, 두 가지 영리기관이며, “국가R&D사업관리서비스”에 매년 등록 관리되는 여섯 가지 핵 심 R&D 성과 항목 중 특히, 특허등록, 매출액, 두 가지를 분석 대상으로 선정한다. 또한, 타 기관 간 R&D 협력 여부도 영향요인으로 본 연구에 포함한다. 일반적인 R&D 논리모형에 기 초하여 예측모형을 수립하며, 분석 샘플 n = 1,929개 종료 R&D 과제를 대상으로 분석 샘플 특성을 고려한 로짓 (Logit) 회귀분석을 실시한다. 실증분석 결과를 요약하면, 첫째, 정부지원 금액 대비 성과창출 성공확률의 양 (+)의 상관성은 확인되나, 그 영향력은 특허등록과 같은 단기적, 기술적 산출에서 매출액과 같은 중기적, 경제적 결과로 진행될수록 감소하였다. 둘째, 매출액 성과창출 여부는 직전 단계에 위치한 특허등록 창출 여부에 의존적임이 확인되었다. 셋째, “단독 R&D”와 비교할 때 “협력 R&D”에서 특허등록, 매출액 성과창출 성공확률이 더 높고, “대기업”보다 “중소기업”의 매출액 성과창출 성공확률이 더 높았다. 넷째, 민감도 실험 설계분석을 통해, 정부지원금액이 증가할수록 특허등록 성과창출 성공확률은 S자형 비선형 성장곡선 형태의 증가 추세를 명확히 보인 반면, 매출액 성과창출 성공확률은 상대적으로 선 형에 근사한 둔감한 증가 추세를 보였다. 본 연구가 제안하는 정책적 함의로서, 각 R&D 과 제별 순차적인 성과창출 유도, 타 기관 간 R&D 협력 활성화, 중소기업 친화적인 국가연구개 발사업의 기획 전개 관리 등이 바람직하다고 판단된다. 또한, 정부지원금액 증액을 통해 성 취 가능한 R&D 성과 항목은 한정적일 수 있으므로, 각 R&D 과제별 정부지원금액 규모의 적절성을 세밀히 검토하는 절차가 향후 좀 더 강화될 필요가 있다고 판단된다.

This study presents an empirical case where a prediction model is estimated for the performance creation success probability regarding a national technology innovation research and development (R&D) program. Additionally, a framework for a design of experiments is established to conduct sensitivity analyses on the predicted probability. The prediction model is developed based on typical R&D logic models, and it encompasses the total of five distinct R&D characteristics such as R&D Government Subsidy (X1), Patent Registration (Y1), Sales (Y2), Company Type (T1) and Collaboration Type (T2). In the analysis, the sample of n = 1,929 observations (i.e., R&D projects) is analyzed using Logit regression models to cope with the sample’s nonparametric characteristics. In particular, an interesting finding from this study is that the predicted probability for Patent Registration (Y1) performance creation success shows an S-shape nonlinear growth curve trend as R&D Government Subsidy (X1) increases. As practical implications, we suggest the following; (1) promoting the sequential R&D performance creation, (2) enabling the R&D collaboration between other agencies, (3) planning, deployment and management for SME-friendly national R&D programs. In addition, a meticulous review process should be incorporated into the R&D management scheme because it was found that the increased amount of R&D Government Subsidy (X1) might have a limited effect up to the short term and technical outputs only.