• Title/Summary/Keyword: Process Monitoring System

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Design of a Condition-based Maintenance Policy Using a Surrogate Variable (대용변수를 이용한 상태기반 보전정책의 설계)

  • Kwon, Hyuck Moo;Hong, Sung Hoon;Lee, Min Koo
    • Journal of Korean Society for Quality Management
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    • v.49 no.3
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    • pp.299-312
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    • 2021
  • Purpose: We provide a condition-based maintenance policy where a surrogate variable is used for monitoring system performance. We constructed a risk function by taking into account the risk and losses accompanied with erroneous decisions. Methods: Assuming a unique degradation process for the performance variable and its specific relationship with the surrogate variable, the maintenance policy is determined. A risk function is developed on the basis of producer's and consumer's risks accompanied with each decision. With a strategic safety factor considered, the optimal threshold value for the surrogate variable is determined based on the risk function. Results: The condition-based maintenance is analyzed from the point of risk. With an assumed safety consideration, the optimal threshold value of the surrogate variable is provided for taking a maintenance action. The optimal solution cannot be obtained in a closed form. An illustrative numerical example and solution is provided with a source code of R program. Conclusion: The study can be applied to situation where a sensor signal is issued if the system performance begins to degrade gradually and reaches eventually its functional failure. The study can be extended to the case where two or more performance variables are connected to a same surrogate variable. Also estimation of the distribution parameters and risk coefficients should be further studied.

Impact localization on a composite plate using multiplexed FBG sensors and error-outlier algorithm (다중화된 FBG 센서와 error-outlier 알고리즘을 이용한 복합재 평판에 대한 충격위치탐지)

  • Park, Sung Yong;Kim, Sang-Woo;Park, Sangyoon
    • Journal of Aerospace System Engineering
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    • v.12 no.6
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    • pp.32-40
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    • 2018
  • An impact localization for a carbon fiber reinforced plastic (CFRP) composite plate was performed using the multiplexed fiber bragg grating (FBG) sensors and the error-outlier based impact localization algorithm. We found that the optimal impact localization with the maximum error of 31.82 mm and the averaged error of 6.31 mm are obtained when the error threshold (ET) and constant level (CL) are 0.3 nm and 110, respectively. Moreover, the detailed process of impact localization under certain optimal parameters and the relevant results were thoroughly investigated. We conclude that the multiplexed FBG sensors and the error-outlier based impact localization algorithm are suitable for an impact localization on composite structures, and expect that they can be utilized for various structural health monitoring (SHM) in the future.

Analysis on the Importance and Competitiveness of Support Services of the Food Service Franchise Headquarters AHP Technique (AHP를 이용한 외식프랜차이즈 가맹본부의 지원서비스의 중요도 및 경쟁력 분석)

  • CHOI, Chaebong;LEE, Sang-Suk
    • The Korean Journal of Franchise Management
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    • v.10 no.4
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    • pp.7-18
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    • 2019
  • Purpose: This study identifies the relative importance of the sub - factors of initial services and continuous services using AHP (Analytic Hierarchy Process) method, and calculates the competitive index for the detailed factors. The purpose of this paper is to propose the establishment of long - term and short - term management strategy for expansion of business of food service franchise, franchisors, long - term and win - win relationship with franchisees, and rationalization of operating system. Research design, data, and methodology: The population for the survey is 92 franchisees in 46 foreign brands and 46 domestic brands in the Seoul metropolitan area (Seoul / Gyeonggi / Incheon). The survey was conducted from July 1 to August 31, 2018 through the survey agency with a telephone interview and a surveyor's direct visit. A total of 100 questionnaires were collected, but a total of 92 parts were used for analysis except 8 parts that were considered to contain false information. Using the AHP method, relative importance and competitiveness index were calculated for the details of initial services and continuous services. Results: The results shows continuous services were significantly higher for both foreign brand franchises, domestic brand franchises, and overall than initial services, This suggests that the continuous services of the affiliated franchisors has a higher relative importance than the initial services. Among the continuous services, brand reinforcement and promotion were significantly higher for both foreign brand merchants and domestic brand franchises. This can be regarded as the most important factor in brand reinforcement and promotion when selecting a food service franchisors. Conclusions: In the Standard Terms and Conditions governed by the Fair Trade Commission, the franchisors should increase the fairness by creating manuals for supporting services, especially after opening, and regularly checking whether the supporting services have been carried out like manuals since the establishment of franchisees. In addition, the Brand Strengthening and Public Relations Committee (tentative name) jointly participated by the franchisors and franchisees for the purpose of strengthening and promoting the brand, suggesting a system for transparent and efficient execution of the brand reinforcement and promotion budget and monitoring afterwards.

A Study of Collaborative and Distributed Multi-agent Path-planning using Reinforcement Learning

  • Kim, Min-Suk
    • Journal of the Korea Society of Computer and Information
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    • v.26 no.3
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    • pp.9-17
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    • 2021
  • In this paper, an autonomous multi-agent path planning using reinforcement learning for monitoring of infrastructures and resources in a computationally distributed system was proposed. Reinforcement-learning-based multi-agent exploratory system in a distributed node enable to evaluate a cumulative reward every action and to provide the optimized knowledge for next available action repeatedly by learning process according to a learning policy. Here, the proposed methods were presented by (a) approach of dynamics-based motion constraints multi-agent path-planning to reduce smaller agent steps toward the given destination(goal), where these agents are able to geographically explore on the environment with initial random-trials versus optimal-trials, (b) approach using agent sub-goal selection to provide more efficient agent exploration(path-planning) to reach the final destination(goal), and (c) approach of reinforcement learning schemes by using the proposed autonomous and asynchronous triggering of agent exploratory phases.

UAV-based Construction Site Monitoring and Analysis System Development for Civil Engineering Management (토목현장에서의 무인비행장치 기반 현장정보 취득 및 분석 시스템 개발)

  • Kim, Changyoon;Youn, Junhee
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.42 no.4
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    • pp.549-557
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    • 2022
  • Due to harsh conditions of construction site, understanding of current feature of terrain and other infrastructures is critical issue for site managers. However, because of difficulties in acquiring the geographical information of the construction sites such as large sites and limited capability of construction workers, comprehensive site investigation of current feature of construction site is not an easy task for construction managers. To address these circumstances of construction sites, this study deduce difficulties and applicabilities of unmanned aerial vehicle in the area of construction site management. To confirm applicability of UAV in civil construction project, case study have been conducted on the road construction project. The result of case study proved that the developed system is one of promising technologies that has been studied in construction site management. To improve applicability of UAV for construction and process management information, law and technical issues will be an important area of future study.

Selection of Tree History Management System Items for Analyzing the Causes of Landscape Tree Defects in an Apartment Complex

  • Park, Sang Wook
    • Journal of People, Plants, and Environment
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    • v.23 no.3
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    • pp.347-362
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    • 2020
  • Background and objective: It is difficult to conclusively determine the exact cause of tree defects since multiple causes are involved such as climate change, plantation, tree quality and planting time, construction, planting base, drainage, sunshine conditions, maintenance, and microclimate. The data related to landscaping construction defects are scattered or fragmented by companies and years, but not managed systematically by the defect information management system. Most of the earlier studies associated with tree defects in apartment complexes suggested defect rates after examining tree defects in the completed construction site and proposed fragmentary and subjective conclusions about the causes of defects observed in trees with high defect rates. It is proposed to continue to conduct studies on the establishment and analysis of systematic databases to identify the exact causes of tree defects and measures to improve, and the need to accumulate systematic data in the construction process where many defects arises. This study was conducted to reduce the defects of trees planted in apartment complexes. Methods: Main factors related to tree defects were subdivided based on the results of literature review and a defect investigation at the completion site, and tree history management items were selected and subdivided during the construction stage. Results: The criteria for the preparation of subdivided items were obtained, and the tree history management checklist was written for the site under actual construction and a systematic database was established. Items that are categorized based to the causes of defects include the location of nurseries, date, tree quality, site conditions, planting techniques, microclimates, and maintenance. Conclusion: This study suggested tree history management items based on the tree defects that can be identified at the construction stage and applied them to the selected study site, which differentiates this study from earlier studies. It will be necessary to conduct a comprehensive and objective time series analysis on tree defects that occur over time by continuously monitoring and collecting data after construction.

A Study on the Role of Locomotion Orientation as an Antecedent of Salespeople' Selling Behavior

  • Lee, Ihn Goo;Ji, Seong Goo
    • Asia Marketing Journal
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    • v.15 no.2
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    • pp.175-194
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    • 2013
  • The purpose of this study is to investigate the effects of the locomotion orientation on salespeople' sales performance with the mediating effect of selling behavior(adaptive selling behavior, SOCO). And we figure out the relationship between customer-oriented selling behavior and adaptive selling behavior because those relationships are not clear. The authors infer research hypotheses based on literature review. We have confirmed the reliability and validity test and those results can be acceptable. Hypotheses test were conducted with structural equation modeling, AMOS. All paths in the research model reasoned by authors have been supported statistically at the significant level. This study with the theoretical implications is as follows. First, this study is the first attempt to investigate the path between locomotion orientation and adaptive selling behavior and SOCO. Secondly, there is an empirical conflict between our study and Franke and Park(2006)'s study. Our study was contradictory to Franke and Park(2006)'s consequences. And so, figuring out clearly those causal paths remains. This study with practical implications are as follows. First of all, the salespeople' selling performance was affected by adaptive selling behavior, customer-oriented selling behavior, and sales-oriented activities, such as the importance of selling behavior once again proven. It is necessary to enhance the capabilities that can be transformed into action appropriate to the needs of customers each sales step-by-step in the process of salespeople for various system through education and incentives, and to interact with customers and understand their customers relative to salespeople will. In order to enhance adaptive selling behavior, the company needs to do educational program and monitoring system with the positional promotion when salespeople get the high adaptive selling behavior. Secondly, the locomotion orientation of the salespeople is to cause this selling behavior. Management style to increase locomotion orientation is needed, which means, salespeople' superior about something should be conducted. In order to stimulate the selling behavior of the salespeople, most supervisors should use some managerial tools such as feedback, engagement, and rewards.

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Standardization of work environment measurement information for constructing exposure surveillance system (노출감시체계 구축을 위한 작업환경측정 정보 표준화)

  • Choi, Sangjun;Jeong, Jee Yoen;Im, Sungguk;Lim, Daesung;Koh, Dong-Hee;Park, Donguk;Park, YunKyung;Kim, Soyeon;Chung, Eunkyo
    • Journal of Korean Society of Occupational and Environmental Hygiene
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    • v.29 no.3
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    • pp.322-335
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    • 2019
  • Objectives: The goal of this study is to standardize industry, process, and job within work environment measurement information. Methods: We selected 180 work environment measurement reports on 30 industries from a database monitored from 2014 to 2016 by the Korea Industrial Health Association. Ten industrial hygienists, each with over five years of experience in measurement, conducted a primary standardization of 180 reports. Two professional industrial hygienists with more than 20 years of experience each reviewed and revised the results of the primary standardization. We also examined the validity on the usefulness of the standardized database by the two industrial hygienists. Results: The final standardization results were classified into eight major categories, 23 sub-major categories, 39 minor categories, 53 unit categories and 70 sub-unit categories in the Korean Standard Industrial Classification (KSIC) 10th revision. A total of 161 processes were standardized, and there were 148 processes with K2B codes. Standard job was coded into 13 job groups including operator, automobile maintenance, nurse, maintenance, manager, excavating machine operator, forklift driver, radiologist, clinical pathologist, signer, researcher, kitchen assistant, and concrete reinforcement ironworker. Conclusions: Although the standardized information in this study may be only a part of the total information, it can be useful for improvement of the K2B system. Additional research is needed for an ongoing clean-up of data in the K2B and re-calibration and reclassification of standard processes until the future national exposure monitoring system is fully established.

Analysis of Rainfall Runoff Delay Effect of Vegetation Unit-type LID System through Rainfall Simulator-based Probable Rainfall Recreation (인공강우기 기반 확률강우재현을 통한 식생유니트형 LID시스템의 우수유출지연 효과분석)

  • Kim, Tae-Han;Park, Jeong-Hyun;Choi, Boo-Hun
    • Journal of the Korean Society of Environmental Restoration Technology
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    • v.22 no.6
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    • pp.115-124
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    • 2019
  • In a climate change environment where heat damage and drought occur during a rainy season such as in 2018, a vegetation-based LID system that enables disaster prevention as well as environment improvement is suggested in lieu of an installation-type LID system that is limited to the prevention of floods. However, the quantification of its performance as against construction cost is limited. This study aims to present an experiment environment and evaluation method on quantitative performance, which is required in order to disseminate the vegetation-based LID system. To this end, a 3rd quartile huff time distribution mass curve was generated for 20-year frequency, 60-minute probable rainfall of 68mm/hr in Cheonan, and effluent was analyzed by recreating artificial rainfall. In order to assess the reliability of the rainfall event simulator, 10 repeat tests were conducted at one-minute intervals for 20 minutes with minimum rainfall intensity of 22.29mm/hr and the maximum rainfall intensity of 140.69mm/hr from the calculated probable rainfall. Effective rainfall as against influent flow was 21.83mm/hr (sd=0.17~1.36, n=20) on average at the minimum rainfall intensity and 142.27mm/hr (sd=1.02~3.25, n=20) on average at the maximum rainfall intensity. In artificial rainfall recreation experiments repeated for three times, the most frequent quartile was found to be the third quartile, which is around 40 minutes after beginning the experiment. The peak flow was observed 70 minutes after beginning the experiment in the experiment zone and after 50 minutes in the control zone. While the control zone recorded the maximum runoff intensity of 2.26mm/min(sd=0.25) 50 minutes after beginning the experiment, the experiment zone recorded the maximum runoff intensity of 0.77mm/min (sd=0.15) 70 minutes after beginning the experiment, which is 20 minutes later than the control zone. Also, the maximum runoff intensity of the experiment zone was 79.6% lower than that of the control zone, which confirmed that vegetation unit-type LID system had rainfall runoff reduction and delay effects. Based on the above findings, the reliability of a lab-level rainfall simulator for monitoring the vegetation-based LID system was reviewed, and maximum runoff intensity reduction and runoff time delay were confirmed. As a result, the study presented a performance evaluation method that can be applied to the pre-design of the vegetation-based LID system for rainfall events on a location before construction.

The Analysis of Maturity on Implementation of Safety and Health Management System in a Construction Company (건설업 안전보건경영시스템 실행의 성숙도 분석)

  • Oh, Byung Sub;Kwon, Chang Hee
    • Journal of the Society of Disaster Information
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    • v.8 no.3
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    • pp.310-318
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    • 2012
  • Actual condition by items based on the level of execution of Construction Company certified by Construction Safety and Health Management Systems (KOSHA 18001) was investigated, analyzed and evaluated reflecting various opinions fincluding safety experts, top management, audit experts, and construction engineers. Currently, the maintenance is being managed through internal audit after the safety and health management system has been certified, but it is difficult to identify the degree of continuous improvement. In order to present the standards to see the level of quantified system, this study was conducted. The purpose of this study is to present the system maturity evaluation tool to be used to reduce occupational accidents through proper establishment and continuous improvement of national health and safety management system. Results of this study are summarized through identification of current condition of implementation of KOSHA 18001 system, development of maturity measurement tool and verification as follows: First, priority of implementation for activities of headquarters and on-site was determined by importance of activities such as the risk assessment, safety and health accident prevention activities, performance assessment and monitoring, resource management and support, and management review and improvement in order. In addition, the expert group presented that association with continuous improvement activities could establish the system by presenting strengths, weaknesses and improvement subjects of system.