• 한국기계가공학회지
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• 제21권8호
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• pp.32-42
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• 2022

Asymptotic tracking of a non-minimum phase nonlinear system has been a popular topic in control theory and application. In this paper, we propose a new control scheme to achieve asymptotic output tracking in anon-minimum phase nonlinear system for periodic trajectories through an iterative learning control with the stable inversion. The proposed design method is robust to parameter uncertainties and periodic external disturbances since it is based on iterative learning. The performance of the proposed algorithm was demonstrated through the simulation results using a typical non-minimum nonlinear system of an inverted pendulum on a cart.

• 한국의상디자인학회지
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• 제13권2호
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• pp.163-173
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• 2011

The objective of this study is to examine the current status of manufacturing formal knit jackets for middle-aged women. Fifteen manufacturers specializing in formal knitwear brands were chosen as the study subjects, and interviews and questionnaires were used with patterners and designers. The questionnaire was composed of 27 items and began with general questions, such as how the jackets were manufactured. Specific questions, such as materials and sewing method, were also considered further on. The results are as follows: First, as for the structure of the knit jacket manufacturer, seven out of fifteen manufacturers directly manufactured knit jackets in their own factory, while the manufacturing was comprised of 20% woven jackets and 80% knit jackets for all manufactures. Second, as for the type of yarn mostly used in knitting the fabric for the jackets, satin yarn and wool were used mostly for F/W with Plain and Half Milano rib stitches as the type of knit with a gauge of 12G and 7G. Third, as for the margin between the product size of the target brand and the size of the body at the time of designing a knit jacket pattern, the investigation of the actual state of manufacturing showed that the margin at the bust was B+4.8cm, the waist was W+6.9cm, and the hip girth was H+5cm. Therefore, the bust and hip girth of the knit jackets were designed to be smaller than those of the bust and hip girth lines of non-flexible woven jackets. On the contrary, the waist measurement of non-flexible woven jacket was designed to be smaller than the knit jacket. It was found that the side line of the knit jacket was expressed with greater give as compared to that of the non-flexible woven jacket.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2009년도 하계학술대회 논문집
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• pp.58-58
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• 2009

Uniformity related issues in chemical mechanical polishing (CMP) are within wafer non-uniformity (WIWNU), wafer to wafer non-uniformity (WTWNU), planarity and dishing/erosion. Here, the WIWNU that originates from spatial distribution of independent variables such as temperature, sliding distance, down force and material removal rate (MRR) during CMP, relies to spatial dependency. Among various sources of spatial irregularity, hardness and modulus of pad and surface roughness in sources for pad uniformity are great, especially. So, we investigated the spatial variation of pad surface characteristics using pad measuring system (PMS) and roughness measuring system. Reduced peak height ($R_{pk}$) of roughness parameter shows a strong correlation with the removal rate, and the distribution of relative sliding distance onwafer during polishing has an effect on the variation of $R_{pk}$ and WIWNU. Also, the results of pad wear profile thorough developed pad profiler well coincides with the kinematical simulation of conditioning, and it can contribute for the enhancement of WIWNU in CMP process.

• 한국경제지리학회지
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• 제25권1호
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• pp.41-59
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• 2022

우리나라 제조업 성장을 견인해 온 산업단지는 지역 단위에서 제조업 집적의 외부효과를 강화하는 수단으로서 기능하는가? 본 연구는 질문의 답을 위해 제조업 집적과 지역경제 생산성 간 관계에서 산업단지 조절효과를 분석함으로써 기존 선행연구에서 다루지 않은 집적효과 논의를 수행하였다. 2010-2019년 기간의 전국 시군구를 대상으로 한 불균형패널자료를 활용하여 패널분석을 실시하였으며, 전국, 수도권 그리고 비수도권을 구분하여 추정한 결과를 제시하였다. 분석 결과 비수도권의 경우 제조업 특화와 다양성 증가에 따른 긍정적 외부효과가 산업단지를 통해 더욱 강화되어 나타나는 환경이 조성된 반면 수도권에서는 산업단지의 조절효과가 제한적인 것으로 나타났다. 이러한 결과는 제조업 집적효과 극대화, 비수도권의 경제 활성화, 제조업 혁신을 위한 정책수단으로서 산업단지 역할을 재조명할 수 있는 측면에서 시사하는 바가 크다.

• 한국직업건강간호학회지
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• 제20권1호
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• pp.93-103
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• 2011

Purpose: This study was conducted to assess reported industrial accidents and non-reported industrial accidents that took place in 63 small and medium sized manufacturing industries located in Daegu and Gyeongsangbuk-do in the year of 2009. Methods: During the period from January to December 2009, the number of industrial accidents that happened each month was examined according to the characteristics of industry, industrial accidents, workers with industrial accidents, treatment, as well as causes and treatment of the non-reported. Results: The total incidence rate of industrial accidents was 3.48%, of which only 0.31% reported. The incidence rate in packing and distribution among manufacturing workplace, and in the industry with 50~99 employees, was higher than the other groups. Of the non-reported, over 80% in required under 10 days of medical treatment, and 56% in required cost of less than 100,000 won. Kappa values were 0.771 concurrence in opinions for causes of non-reported, and 0.571 concurrence in opinions for management termination of non-reported between the employees and employer. Conclusion: It is suggested that more supportive policy and precise, nationwide survey on the actual state of industrial accidents, including non-reported cases, be implemented to efficiently manage industrial accidents.

• 품질경영학회지
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• 제22권4호
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• pp.79-101
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• 1994

In modern manufacturing, a product consists of many components created by different processes. Variations in the individual component dimensions and in the processes may result in unacceptable final assemblies. Thus, engineers have increased pressure to properly set tolerance specifications for individual components and to control manufacturing processes. When a proper variation stack-up analysis is not performed for all of the components in a functional system, all component parts can be within specifications, but the final assembly may not be functional. Thus, in order to improve the performance of the final assembly, a proper variation stack-up analysis is essential for specifying dimensional tolerances and process control. This research provides a detailed case example of the use of variation stack-up analysis using a Monte Carlo simulation method to improve the defect rate of a complex process, which is the commutator brush track undercut process of an armature assembly of a small motor. Variations in individual component dimensions and process mean shifts cause high defect rate, Since some dimensional characteristics have non-normal distributions and the stack-up function is non-linear, the Monte Carlo simulation method is used.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2002년도 추계학술대회 논문집
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• pp.280-285
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• 2002

Copy machines have been used in the 3 dimensional shape machining like the non-sphere surface. This study is intended to show the possibility of manufacturing of a non-sphere shape without a exclusive CAM(Computer Aided Manufacturing) software in the process of metallic mold. It has been examined under the two types of working conditions. One is a cutting by manual programming and the other is a cutting by a general-purpose CAM software. Two kinds of output data were compared and analyzed, and data by a manual program were discovered more accurate than those of a general-purpose CAM software. In this study, I came to a conclusion it is possible to manufacture a 3 dimensional shape without a exclusive CAM software.

• 한국포장학회지
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• 제9권1호
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• pp.1-6
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• 2003

The partitioning behavior of five printing ink solvents was studied in various cookie ingredients before and after baking which had different water content and different structure. Solvents were ethyl acetate, hexane, isopropanol, methyl ethyl ketone, and toluene which represent different characteristic functional groups. Gas chromatography (G.C.) was used to measure partitioning values at $25^{\circ}C$ on each raw and baked cookie ingredients. Baking condition of cookie ingredients was $260^{\circ}C$ for 10 min. In cookie ingredients, decreases in water content generally affected Kp of polar solvents, but did not affect that of the non-polar solvents. However, as water content decreased in the cookie ingredient, the Kp of the non-polar and polar solvents showed mixed results.

• Journal of Korea Trade
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• 제26권3호
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• pp.102-116
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• 2022

Purpose - This paper empirically investigates the relationship between firm productivity and importing intermediate inputs in the Korean manufacturing sector. Design/methodology - This paper tests the two related hypotheses on the relationship between importing and productivity for a sample of Korean manufacturing firms. We test the self-selection hypothesis by comparing pre-entry levels of productivity between importers and non-importers. We test the learning-by-importing hypothesis by employing propensity score matching with differencein-differences approach. Findings - Future importers are more productive than future non-importers years before they start to import, which supports the self-selection hypothesis. In contrast, there is no strong evidence for learning-by-importing. Originality/value - This paper is the first study to explore the relationship between importing and firm-level productivity for Korean firms. The results have an important implication on trade policies to lower or raise trade barriers in imported inputs.

• The Journal of Asian Finance, Economics and Business
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• 제9권1호
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• pp.35-42
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• 2022

The paper aims to examine the impact of exports on the growth of Vietnamese manufacturing small and medium-sized enterprises (SMEs) by exploring the information of 36,053 enterprises across 24 manufacturing sectors from the Vietnam Annual Enterprise Survey (VAES) in the period 2014-2019. To deal with the problem of variable variance, autocorrelation, and endogeneity of the model, the paper uses the OLS regression method with a strong standard error method and system GMM. Export participation by SMEs is positively associated with business growth in terms of sales and total assets, according to the findings. The GMM estimate shows that the rate of sales growth among exporters is 36.5 percent greater than that of non-exporting enterprises in the case of the sales growth measure. Exporters' average total asset growth rate is 19% greater than the rate estimated for non-exporting businesses. The study's findings indicate the need of adopting policies that promote SMEs in transition economies like Vietnam to engage in exporting activities. Furthermore, the findings show that financial assistance and suitable ownership would enable SMEs to take advantage of export opportunities to increase sales and total assets.