• Journal of Korean Society of Industrial and Systems Engineering
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• v.44 no.2
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• pp.115-123
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• 2021

A lot of sensor and control signals is generated by an industrial controller and related internet-of-things in discrete manufacturing system. The acquired signals are such records indicating whether several process operations have been correctly conducted or not in the system, therefore they are usually composed of binary numbers. For example, once a certain sensor turns on, the corresponding value is changed from 0 to 1, and it means the process is finished the previous operation and ready to conduct next operation. If an actuator starts to move, the corresponding value is changed from 0 to 1 and it indicates the corresponding operation is been conducting. Because traditional fault detection approaches are generally conducted with analog sensor signals and the signals show stationary during normal operation states, it is not simple to identify whether the manufacturing process works properly via conventional fault detection methods. However, digital control signals collected from a programmable logic controller continuously vary during normal process operation in order to show inherent sequence information which indicates the conducting operation tasks. Therefore, in this research, it is proposed to a recurrent neural network-based fault detection approach for considering sequential patterns in normal states of the manufacturing process. Using the constructed long short-term memory based fault detection, it is possible to predict the next control signals and detect faulty states by compared the predicted and real control signals in real-time. We validated and verified the proposed fault detection methods using digital control signals which are collected from a laser marking process, and the method provide good detection performance only using binary values.

• Journal of Korean society of Dental Hygiene
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• v.9 no.4
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• pp.559-568
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• 2009

Objectives : In order to manage to reformative tendency of the educational whole with change request of dental hygienics education which is diversificated and professionalized the manufacturing practice of a temporary resin jacket which is educated with from much dental hygiene is become accomplished, so far also the recognition which relates with the manufacturing practice of a temporary resin jacket of dental hygiene students there is not researched. The present research carried out the practice evaluation with the target of students of a dental hygiene department, who finished a manufacturing practice of a temporary resin jacket, analyzed and investigated the material, reported its result, and enforced a research. Methods : This research selected students of 6 dental hygiene departments located in the Daegu Gyeongbuk region, who have manufacturing experience of a temporary resin jacket, by a convenient sampling method, and then a questionnaire was executed by a self-administration method, and a total of 290 copies were statistically treated. The content of the questionnaire are composed of 2 questions on an attitude survey before and after manufacturing practice of a temporary resin jacket, 3 questions on an educator for practice of a temporary resin jacket, 7 questions on recognition of technical skills for manufacturing a temporary resin jacket, 9 questions on the practice content evaluation of manufacturing of a temporary resin jacket and recognition on manufacturing practice of a the temporary resin jacket. Results : 1. The average of recognition on technical skills for manufacturing a temporary resin jacket of a dental hygienist was 3.82 points, the average of evaluation on practice content of manufacturing a temporary resin jacket being 3.75 points, and the average of recognition on the practice of manufacturing a temporary resin jacket was 3.71 points. 2. Currently, as the educator for the practice of manufacturing a temporary resin jacket, dental hygienists were 188 persons(64.8%) and dental technicians was 102 persons(35.2%), and as educators they want in the future, dental hygienists were 97 persons(33.3%) and dental technicians was 193 persons(66.7%). Persons hoping reeducation for manufacturing a temporary resin jacket were 219 persons(85.9%). 3. There was a significant difference in consciousness of students before and after practice of manufacturing a temporary resin jacket(p<.001). 4. There was a significant difference in practice evaluation and practice recognition according to the educational subject(p<.001). 5. There was a significant reverse correlation in the educational subject, practice evaluation and practice recognition(p<0.01). Conclusions : The practice for manufacturing a temporary resin jacket in education of dental hygiene is necessary to improve job performance ability in more various and specialized dental treatment and to solve desire for improvement of professional technical skill ability of students, and accordingly. About study process of the future students observation investigation or student objective interview investigation etc. seeks a problem in the become research lead, the succeeding research which gropes the plan which is the possibility of solving the problem which discovered is thought will be necessary.

• Journal of Technology Innovation
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• v.7 no.1
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• pp.14-35
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• 1999

This paper presents the relationship between the pace of structural change and the magnitude of employment growth in the manufacturing sector in OECD countries. To measure the pace of structural change, the compositional change index in value-added in manufacturing sector is introduced. For mid to long-term there seems to be a positive relationship between the pace of structural change and the magnitude of employment growth. In those countries with higher value of the compositional index, the employment growth in manufacturing sector was generally higher. To analyse the characteristics of structural change in manufacturing sector, this paper classifies manufacturing industries into groups: one based on technology, one on orientation, one on wages and one on skills. The international comparison of manufacturing sector's employment patterns based on above four classifications are presented. International comparison suggests that Korean manufacturing sector move into jobs with more skills and knowledge The structural change of SMEs and large firms are compared based on above four classification methods. It is shown that SMEs' employment in low value sectors, that is low-technology, labor-intensive, tow-wage, and unskilled sectors, have risen faster than SMEs' employment in high-technology, science-based, high-wage and skilled sectors. Large firms' employment have been mainly increased in high value sectors. However, the employment growth of both large and small firms have been concentrated on production worker-intensively-using sectors, i.e. unskilled sectors. This widened the wage differential of production workers by firm sizes and concurrently led to severe shortage of production workers for SMEs, which has little ability to pay high wage to production workers because they usually belong to low-wage sectors. Korea need to push SMEs forward to high value sectors. The premise of that is, however, to pull large firms out of production worker-intensively-using sectors.

• The Journal of Korean Academy of Prosthodontics
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• v.59 no.4
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• pp.442-450
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• 2021

The CAD-CAM technique is a rapidly developing field in the dental field and is applied to various fields of prosthetic treatment. Among them, the manufacturing of dentures using the milling technique classified as subtractive manufacturing is one of the commercialized digital full denture manufacturing methods. At the same time, it is possible to more efficiently manufacture a metal framework for implant overdenture by selective laser sintering or melting technique classified as an additive manufacturing method. The purpose of this article is to describe the fabrication of CAD-CAM maxillary complete denture and mandibular implant overdenture as well as its features.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.21 no.8
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• pp.25-31
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• 2022

Recently, investment in the aerospace industry has increased, and titanium alloys have been widely adopted for manufacturing parts in the aerospace industry. The Ti-6Al-4V alloy has high strength in high-temperature and high-pressure environments and is evaluated as a material with excellent heat, corrosion, and abrasion. However, titanium alloys are expensive, difficult to cut, and possess a large cutting load during the drilling process. In this study, the cutting force generated in the drilling process of Ti-6Al-4V alloy was verified via finite element analysis (FEM) and cutting force measurement experiments. A structural analysis was performed based on the cutting analysis data to verify the plastic deformation occurring during the drilling process of cylindrical Ti-6Al-4V alloy aircraft parts. Methods were proposed to predict the amount of deformation that occur during the manufacturing process of titanium-alloy aircraft parts and control the external environment, to minimize the amount of deformation.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.33 no.1
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• pp.50-59
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• 2023

Objectives: This study was designed to examine the effect of risk assessment on employee safety behavior in manufacturing workplaces. In addition, this study attempted to explore factors related to the occupational safety and health system in the workplace affect the risk assessment of manufacturing sites. Methods: This research is a cross-sectional study using the Korea Occupational Safety and Health Agency's 2018 Occupational Safety and Health data. The sample for study is 1,967 manufacturing workplaces. Data were analyzed using descriptive statistics, t-test, ANOVA, chi-square test, and hierarchical multiple regression analysis using SPSS (ver.25.0). Results: As a result of the multiple hierarchical regression analysis, it was found that risk assessment had an effect on employee safety behavior (t=4.435, p=<.001). Furthermore, the size of the workplace affected employee safety behavior (t=2.494, p=<.001). In addition, the presence of safety and health management organizations affected employee safety behavior (t=4.301, p=<.001). The factors of the safety and health organization (𝑥²=35.245, p=<.001), the occupational safety and health committee (𝑥²=149.440, p=<.001), and the supervisor (𝑥²=16.472, p=<.001) were identified as factors that increased the possibility of risk assessment in the manufacturing workplaces. Conclusions: In this study, it was found that risk assessment is a factor that increases the level of workers' safety behavior in manufacturing workplaces. Therefore, it is necessary to provide institutional support for activating risk assessment at manufacturing workplaces.

• Journal of Aerospace System Engineering
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• v.14 no.5
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• pp.73-82
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• 2020

Recently, there has been an increase in additive manufacturing for the fabrication of liquid rocket engines. This technology can innovate conventional fabrication methods to reduce the lead time and manufacturing cost and can enhance the performances such as weight reduction. In this study, a literature survey is presented that includes types, advantages, disadvantages, and foreign government-based projects of the technology related to liquid rocket engine manufacturing. The present survey focuses on the technology that has been applied to various components such as turbopumps and valves while much larger efforts are made for combustion chambers with regenerative cooling channels and diverging nozzles, as the advantages of the technology are maximized for the applications.

• The Korean Journal of Health Service Management
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• v.11 no.1
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• pp.107-115
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• 2017

Objectives : The purpose of this study was to examine the relationship between the health behavior and prevalence of chronic diseases among manufacturing workers. It would provide fundamental data in the development of health promotion programs for manufacturing workers. Methods : Data on 3,171 employees who underwent health check-ups by the National Health Insurance Service in L company, G City from March to December 2014 were analyzed. The statistical analysis of frequency, chi-square test, and multiple logistic regressions were performed using SPSS 18 program. Results : The results of this study show that obesity and over-weight are the health behaviors that influence the prevalence of chronic diseases in manufacturing employees. Conclusions : The implementation of public health projects to improve the voluntary participation of the employees can enhance their health, improve the productivity, and influence their quality of life positively by changing the health behaviors.

• IE interfaces
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• v.15 no.3
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• pp.230-240
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• 2002

Information technologies centered on the internet in the area of shipbuilding and marine engineering further incur the needs to increase the flexibility of the organization, the dispersion of work process, and the use of out sourcing, as well as the globalization of related market. In near future, electronic commerce and concurrent engineering based on CALS/EC and the Internet will be an integral part of the environment and upon these changes, ship design and construction will become a computer supported cooperative work of many dispersed and specialized groups. As the means of active response to these environmental changes, many new concepts such as digital shipbuilding, virtual shipyard, and simulation based design are appearing. In this paper, the concept and current status of digital manufacturing in general manufacturing industry will be reviewed. Then, related technologies, area of application and methods of digital manufacturing in shipbuilding and marine industries are presented. In addition, virtual assembly simulation system for shipbuilding(VASSS), a tool for crane operability and block erection simulation in virtual dock based on 3D product model, will be introduced.

• Journal of Biosystems Engineering
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• v.40 no.4
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• pp.320-326
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• 2015

Purpose: Kimbugak is one of Korea's traditional snack foods made of laver. Mechanization of the manufacturing process is necessary to produce kimbugak in large quantities and standardize the products for industrialization. This study was conducted to develop a machine that can simultaneously accomplish the two processes of pasting and garnishing for manufacturing kimbugak, and test its performance. Methods: A pasting and garnishing machine was designed, and its target work efficiency was set at 720 sheets/h. The performance was tested based on the physical characteristics such as work efficiency, pasting uniformity, and garnishing uniformity. Results: With the developed technology, kimbugak could be produced up to a productive rate of 840 sheets/h on a single machine. The pasting uniformity ranged from 91.5% to 96.8%, and a garnishing uniformity of more than 90% could be obtained. Conclusions: It is expected that this approach to developing a machine with the functions of pasting and garnishing can contribute to the mechanization of the manufacturing process to produce Korean traditional foods including kimbugak in large quantities and standardize the products for industrialization.