In the manufacturing industry, dispatching systems play a crucial role in enhancing production efficiency and optimizing production volume. However, in dynamic production environments, conventional static dispatching methods struggle to adapt to various environmental conditions and constraints, leading to problems such as reduced production volume, delays, and resource wastage. Therefore, there is a need for dynamic dispatching methods that can quickly adapt to changes in the environment. In this study, we aim to develop an agent-based model that considers dynamic situations through interaction between agents. Additionally, we intend to utilize the Q-learning algorithm, which possesses the characteristics of temporal difference (TD) learning, to automatically update and adapt to dynamic situations. This means that Q-learning can effectively consider dynamic environments by sensitively responding to changes in the state space and selecting optimal dispatching rules accordingly. The state space includes information such as inventory and work-in-process levels, order fulfilment status, and machine status, which are used to select the optimal dispatching rules. Furthermore, we aim to minimize total tardiness and the number of setup changes using reinforcement learning. Finally, we will develop a dynamic dispatching system using Q-learning and compare its performance with conventional static dispatching methods.

Up to date cosmetic OEM/ODM (original equipment manufacturing/original development manufacturing) industry receives attention as a future growth engine due to steady growth. However, because of limited research and development capability, many companies have employed commercial management platforms specialized for large-sized companies; thus, overall system effectiveness and efficiency is low. Especially, MRP (material requirement planning) system introduced originally in 1970s is employed to calculate the requirement of the parts. However, dynamic nature of production lead time usually results in incorrect requirements. In addition, its algorithm does not consider the capability of the production resources. Also, because the commercial MRP system calculates all subcomponent for fixed period, the more goods have subcomponent, the slower calculation is. Therefore, conventional MRP system cannot respond complicated situation in time. In this study, we will suggest a new method that can respond to complicated situations resulting from short lead time and urgent production order in Korean cosmetic market. In particular, a distributed MRP system is proposed, that consists of multi-functional and operational modules, based on the characteristic of the BOM (bill of material). The distributed MRP system divides components (i.e. products and parts) into several fields and decrease the problem size; thus, we can respond to dynamically changed data any time. Through this solution, we can order components quickly, adjust schedules and planned quantity, and manage stocks reasonably. In addition, a prototype of the distributed MRP system is presented in this paper, in which ERP (enterprise resource planning) sever data is associated with an excel spreadsheet via MSsql. System user interface is implemented by a VBA (visual basic for applications) tool. According to a case study, response rate for delivery and planning achievement rate were enhanced about 20%, and inventory turnover was also decreased. Consequently, the proposed system improves overall profit.

The up-to-date business environment for Korean manufacturers is very complex and rapidly changing. Especially, the companies have faced with various changes derived from small quantity batch production, diversification of customer demands, and short life cycles of products. Consequently, the Korean manufacturing companies are in need of more efficient production planning and scheduling techniques. In this paper, the research trend of scheduling techniques is investigated to provide relevant information to researchers in this field. Furthermore, some implications for future researches are presented regarding literatures published in Korea over the last 10 years. This paper presents an entire investigation into Korean research works on scheduling (2,569 papers) that are published from 2007 to 2016. Especially, detailed analysis was carried out in the following three industry : 1) semiconductor, 2) shipbuilding and 3) automobile. In this paper, approaches to scheduling presented in the literature are categorized into the following three categories : 1) application, 2) algorithm, and 3) simulation modeling. First, in the semiconductor industry, scheduling techniques related to semiconductor cleaning processes, photolithography processes, chemical processes, transport and transport equipment have been found to be dominant. Second, the shipbuilding industry is focused on assembly processes, transporter, crane and various existing production management system. On the other hand, the scheduling research of the automobile industry is mainly focused on the vehicle movement routing and procurement supply-chain planning algorithm in terms of logistics. The conclusion of this study are expected to provide many implications for various types of academic and practical follow-up studies related to scheduling in consideration of main characteristics of semiconductor, shipbuilding and automobile industries.

Today, the management environment of the manufacturing industry is faced with drastic changes. The manufacturing industry is planning to innovate for itself via upgrading manufacturing technology and securing manufacturing competitiveness through 'Industry 4.0' and 'Manufacturing 3.0' strategies combined with ICT (information and communications technologies) for smart factory construction. In addition, as the era of the fourth industrial revolution began, the smart factory is emerging as a new paradigm that can lead to new changes in the manufacturing industry and achieve sustainable development. However, most of SMEs (small and medium-sized manufacturing enterprises) in Korea have very low technology, investment capital and expertise for smartization, and the level of informatization is so low that they cannot build basic systems such as a management module of production records. Therefore, this study proposes a framework that integrates cloud-based production data management and production scheduling with intuitive rules for smart production site management of SMEs. The main features of the proposed framework for SMEs are as follows: 1) the collection and management of production data using the cloud system; 2) operation management using intuitive heuristic algorithm; 3) production scheduling through timing constraints-based simulation.

Up-to-date manufacturing companies have faced a market-driven environment of pull production order. There should be a difference in operating manufacturing resources according to the type, quantity, and delivery time of manufactured products, because the process situation in pull production is changed by customer orders. And it should be taken into account from the stage of preparing for production such as process design and the placement and utilization of manufacturing resources. However, the feasibility of production plans is limited because most of small manufacturing businesses make production/supply plan of the parts and products assuming that equipment abilities in scheduling is sufficient without managing process standard information systemically. In this study, a discrete event simulation system based on BOM (bill of material), that is F-OPIS (online productivity innovation system), is introduced and a case study on application of the system leading to improving productivities is presented. F-OPIS deals with a decision-problem on production management and it is specialized for small-and- medium sized manufacturing companies. The target company of this case study is a typical small-and-medium sized manufacturing company in Korea, that produces various machined parts. The target company adopts make-to-stock production management to prevent tardy delivery because of fluctuations in demand. Therefore, it is required to apply an efficient inventory control solution for improving productivities. In this paper, based on the constraints of working capacity of manufacturing resources, the bottleneck process is analyzed as production conditions are changed. Consequently, an improvement plan is proposed, that eventually enhances overall utilization rates of resources in the bottleneck process and reduces overall production lead-time and inventory level.

The up-to-date small and medium-sized enterprises (SMEs) in Korea have tried to respond flexibly and rapidly to dynamic business environment and to establish efficient production management system based on information technologies. However, most of SMEs have faced with low applicability of the production management system resulting from high costs of introduction and maintenance. In this paper, a production planning and control system, that is S-PMS (production management system for SMEs), is proposed to solve the problem of low applicability and limited human resources. S-PMS enables production managers to efficiently collect and manage master data with the actual target production systems and explores the bottleneck process by means of simulation techniques to improve productivity. Furthermore, it implements rescheduling mechanism in terms of a variety of process routes. In essence, intuitive dispatching rules and integrated data management of S-PMS improve field applicability of production management system. Consequently, S-PMS is expected to be used as an efficient production management system of SMEs in Korea.

Up-to-date business environment for manufacturers is very complex and rapidly changing. In other words, companies are facing a variety of changes, such as diversifying customer requirements, shortening product life cycles, and switching to small quantity batch production. In this situation, the companies are introducing the concept of JIT (just-in-time) to solve the problem of on-time production and on-time delivery for survival. Though many companies have introduced ERP (enterprise resource planning) systems and MRP (material requirement planning) systems, the performance of these systems seems to fall short of expectations. In this paper, the case study on introducing an APS (advanced planning and scheduling) system based on dispatching rules to a machining company and on finding a method to establish an efficient production schedule is presented. The case company has trouble creating an effective production plan and schedule, even though it is equipped with an MRP-based ERP system. The APS system is applied to CNC (computer numerical control) machines, which are key machines of the case company. The overall progress of this research is as follows. First, we collect and analyze the master data on individual products and processes of the case company in order to build a production scheduling model. Second, we perform a pre-allocation simulation based on dispatching rules in order to calculate the priority of each order. Third, we perform a set of production simulations applying the priority value in order to evaluate production lead time and tardiness of pre-defined dispatching rules. Finally, we select the optimal dispatching rule suitable for work situation of the case company. As a result, an improved production schedule leads to an increase in production and reduced production lead time.

목 적 : MRCP Study는 간담계 및 췌장부위의 질환을 조사하는데 있어 비침습적으로 유용하게 사용되는 진단 방법이다. 다양한 간담췌관계의 질환에서 MRCP의 진단적 유용성과 정확성에 대해 보고 되었고 자기공명 간담췌관조영술(MRCP)이 담관결석을 진단하거나 담도의 해부학적 구조를 관찰하는데 있어 내시경역행간담췌관조영술(ERCP)을 대체 할 수 있다고 보고 되었다. 이에 MRCP Study중 3D 영상구현이 가능한 T2 space rst cor 검사시 환자의 체형과 몸무게에 따른 영상의 화질 차이점을 알아보고 진단적 유용성을 비교분석 평가하고자 하였다. 대상 및 방법 : 본원에서 2013년 03월부터 2014년 02월까지 을지대학교병원에서 MRCP 검사를 시행한 34명을 대상으로 하였다. 34명중 남자 18명, 여자 16명, 평균연령은 55세이다. 검사장비는 siemens Skyra3.0T를 이용하였고 Parameter는 FOV 350mm, TR 2400ms, TE 695ms, Slice Thickness 1.0mm, Flip angle 120deg, Resolution 384×384 (ipat grappa factor3), Bandwidth 352Hz/px로 Trigger gating mode를 Phase scout mode와 Liver dome mode를 각각 검사하여 결과 분석은 영상의학과 복부전문의 1명, 전공의 2명, MR전문 방사선사 2명이 정성적으로 평가하였다. 결 과 : 검사 대상자들을 BMI 지수에 따라 구분하였고 영상의 분석결과 과체중 집단에서는 phase scout mode는 과체중 15명, 정상체중 4명이 우위를 나타냈고, liver dome mode는 과체중 5명, 정상체중 10명이 우위로 분석되었다. 검사 소요시간은 phase scout mode 5분 21초, liver dome mode 4분 36초로 41초정도의 차이로 평균검사시간은 liver dome mode가 적게 소요되었다. 결 론 : MRI 검사에 있어 그 목적에 맞는 sequence와 parameter를 적용하는 일은 임상검사에서 유용한 영상을 얻어내는데 있어 매우 중요하다. 그 중 MRCP 검사에 있어서도 환자의 체형이나 연령에 따라 적당한 검사방법을 택함으로써 획득되는 최종 영상의 질은 확연히 달라진다. 본 연구에서 34명의 검사자들을 대상으로 liver dome mode와 phase scout mode를 시행하여 과체중은 phase scout mode, 정상체중은 liver dome mode를 이용하여 검사하는 것이 유용함을 확인할 수 있었다.

목 적 : 고자장 3.0T MRI가 보편화되면서 임상에서 다양하게 이용되고 있다. 특히 척추 질환의 병리적 감별에 있어 지방 신호를 제거하는 지방억제기법이 유용하게 이용되고 있다. 본 연구에서는 자체 제작한 phantom 영상을 획득하고 element의 signal intensity와 homogeneity를 분석하고자 한다. 또한 임상영상을 평가하고 각 지방억제기법의 장·단점을 비교·분석하여 최적의 지방억제를 위한 방법을 제시하고자 한다. 대상 및 방법 : 본 연구를 위하여 자체 제작한 phantom을 CHESS, SPAIR, STIR, Dixon sequence로 검사하여 각각 5개의 coronal 영상을 획득 한다. 5개의 영상 중 3번째 영상에서 1~25번까지 설정된 ROI의 signal intensity를 측정하여 평균과 변동계수를 산출한다. 임상영상에서는 Brain, C-spine, L-spine을 분석하여 유용한 기법을 평가 한다. 결 과 : Phantom영상의 Signal Intensity는 CHESS>Dixon>STIR>SPAIR로 SPAIR의 영상이 지방소거가 가장 양호하게 분석되었고, CHESS는 영상의 중심부로 부터 멀어질수록 지방제거가 현저하게 저하되었다. 영상의 변동계수는 CHESS>SPAIR>STIR>Dixon 으로 전체 영상의 homogeneity는 Dixon이 가장 양호하였다. Brain 임상영상의 지방억제는 STIR가, homogeneity는 Dixon이 양호하였다. C-spine은 STIR와 Dixon이 지방억제, homogeneity 모두 양호하였다. L-spine은 SPAIR와 CHESS의 지방억제가 양호하였고, homogeneity는 Dixon, STIR가 양호하였다. 결 론 : Phantom 영상의 지방제거는 SPAIR, STIR가 가장 우수하였고, 영상의 homogeneity는 Dixon이 가장 양호한 영상으로 평가 되었다. 환자를 대상으로 한 임상검사에서는 Brain 임상영상의 지방억제는 STIR가, homogeneity는 Dixon이 양호하였다. C-spine은 STIR와 Dixon이 지방억제, homogeneity 모두 양호하였다. L-spine의 지방억제는 SPAIR와 CHESS가, homogeneity는 Dixon, STIR가 양호하였다.

In this study, the masking effect of olfactory stimulus on the awakening state due to sound stimuli while driving using Graphic Driving Simulator was observed through the response of autonomic nervous system. The test was conducted for 11 males in their twenties. The siren of ambulance car was presented to them as auditory stimulus for 30 secs while driving in a situation of high way in the condition of both peppermint and control, respectively, and LF/HF ratio of HRV (Heart Rate Variability), the activity index of sympathetic nerve, and GSR (Galvanic Skin Response) response were examined. The test was proceeded in the order of three stages, that is, sound stimuli (test 1), driving performance, and sound stimuli (test 2), and fragrance stimulus, driving performance, and sound stimuli (test 3), and the physiological signal of GSR, HRV was measured in the whole stages. As a result of test, comparing the results of before and after auditory stimulus test (1) (p < 0.01), test (2) (p < 0.05), and test (3) (p <0.01), driving performance test (2) (p < 0.01), test (3) (p < 0.01), and olfactory stimulus test (3) (p < 0.05), respectively, GSR response increased, showing significant difference in all the tests. It indicates that when auditory stimulus was presented to the subjects, they were in the awakening state as sympathetic nervous system got activated. As a result of comparing auditory stimulus while driving before and after presenting olfactory stimulus, there was no significant difference in GSR response. The LF/HF ratio of HRV increased, showing a significant difference only in test (2) (p < 0.05), and in driving performance test (2) (p < 0.05) in auditory stimulus, however, it showed no significant difference in olfactory stimulus. As a result of comparing auditory stimulus while driving before and after presenting olfactory stimulus, there was a decrease, showing significant difference (p < 0.05) in LF/HF ratio of HRV. That is, it means that the activation of sympathetic nervous system decreased, and that parasympathetic nervous system got activated. From these results, it was observed that while driving, the awakening level due to auditory stimulus was settled with olfactory stimulus. In conclusion, it was drawn that while driving, olfactory stimulus could have the masking effect on auditory stimulus.

In this study, it was observed through the ability of performing secondary tasks and baseline fetal heart rate how the supply of lavender, peppermint and highly concentrated oxygen (40%) affected distraction due to the performance of secondary tasks in the driving environment. Twelve male university students conducted secondary tasks while driving in the environments (6 in total) mixed and designed with oxygen concentration (21%, 40%) and the condition of odors (Normal, Lavender, Peppermint). The test was proceeded in order of stable state (5mins), driving (5mins), and secondary tasks (1min), and by extracting ECG data from every section by 30secs, the mean value of baseline fetal heart rate was calculated. As a result of analysis, in the ability of performing secondary tasks, a percentage of correct answers showed no difference in oxygen concentration and the condition of odors (p > 0.05). In performance completion time, a percentage of correct answers decreased showing a statistically significant difference in the condition of odors compared with the condition where odors were not provided (p < 0.05). As for baseline fetal heart rate, in the comparison between sections, while performing secondary tasks, it increased showing a significant difference compared with stable state and driving state (p < 0.05). The effect of interaction was observed in oxygen concentration and the condition of odors. When odors were not provided, baseline fetal heart rate decreased in 40% oxygen concentration compared with 21% oxygen concentration (p < 0.05), however, when peppermint was provided, it increased in 40% oxygen concentration compared with 21% oxygen concentration (p < 0.05). In conclusion, the fact that the condition of odors increased the ability of calculation, and when only the highly concentrated oxygen was provided, parasympathetic nerve system was activated, however, when highly concentrated oxygen was provided with peppermint at the same time, sympathetic nervous system (sns) was activated, which had a negative effect on the autonomic nervous system was drawn.