• 산업공학
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• 제12권1호
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• pp.10-18
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• 1999

Job shop manufacturing environments are using the concept of cellular manufacturing systems(CMS) which has several advantages in reducing production lead times, setup times, work-in-process, etc. Utilizing the similarities between cell-machine, part-machine, and the shape/size of parts, CMS can group machines and parts resulting in improved efficiency of this system. However, when grouping machines and parts in machine cells, there inevitably occurs exceptional elements(EEs), which can not operate in the same machine cell. Minimizing these EEs in CMS is a critical point that improving production efficiency. Constraints in machine duplication cost, machining process technology, machining capability, and factory space limitations are main problems that prevent achiving the goal of maintaining an ideal CMS environment. This paper presents an algorithm that minimizes EEs under the constraints of machine duplication cost and factory space limitation. Developing exceptional operation similarity(EOS) by cell-machine incidence matrix and part-machine incidence matrix, it brings the machine cells that operate the parts or not. A mathematical model to minimize machine duplication is developed by EOS, followed by a heuristic algorithm in order to reflect dynamic situation resulting from minimizing exceptional elements process and the mathematical model. A numerical example is provided to illustrate the algorithm.

• 제어로봇시스템학회논문지
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• 제12권6호
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• pp.600-607
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• 2006

For the effective operation of manufacturing system, FMS(Flexible Manufacturing System) and CIM(Computer Integrated Manufacturing) system are developed. In these systems, a machine tool is the target of integration in last 3 decades. In nowadays, the conventional concept of machine tools is changing to the autonomous manufacturing device based on knowledge-evolution through applying advanced information technology in which open architecture controller, high speed network and internet technology are contained. In this environment, a machine tool is not the target of integration but the subject of cooperation. In the future, a machine tool will be more improved in the form of a knowledge-evolution based device. In order to develop the knowledge-evolution based machine tools, this paper proposes the structure of knowledge evolution in M2M(Machine To Machine) and the scheme of a dialogue agent among agent-based modules such as a sensory module, a dialogue module, and an expert system. The dialogue agent has a role of interfacing with another machine for cooperation. To design the dialogue agent module in M2M environment, FIPA-OS and ping agent based on FIPA-OS are analyzed in this study. Through this, it is expected that the dialogue agent module can be more efficiently designed and the knowledge-evolution based machine tools can be hereafter more easily implemented.

• 전기학회논문지
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• 제64권5호
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• pp.824-829
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• 2015

The rotary type testing machine undergoes mechanical stress as an external force is applied. In case of the rotary type testing machine, even a tiny flaw results in a fatal demage because the size of the machine is huge. Therefore, when designing the rotary type testing machine, it is necessary to secure a safety factor with the mechanical stress analysis in order to prevent the machine from being destroyed due to scattering or transformation of rotating field. This thesis proposes a LSM rotary type tesitng machine which rotates at the speed of up to 600km/h. And the mechanical stress is considered in order that the safety factor remains above 1.5 at the maximum speed. In addition, because normal force as well as thrust occurs in the machine, the normal force exerted was considered through the strength analysis. Finally, a design plan which enables to weaken the normal force affecting the rotary type testing machine is introduced and its validity is proved by the results of FEM analysis.

• 한국의상디자인학회지
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• 제24권4호
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• pp.87-99
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• 2022

The purpose of this study is to develop machine embroidery textile designs for each technique that can be expressed using a single-headed computer embroidery sewing machine through a machine embroidery CAD system. For research, embroidery CAD utilized the Artistic digitizer, and the guillotine computer-mechanical magnetization machine used ELNA. The design concept was limited to portraits and relics of independence activists in six memorial halls built in Korea. The results of this study are as follows. First, it was found that the machine embroidery texture, which could only be produced by industries in the past, can be expand in the infinite creative embroidery design area by enabling the digitalization of motif images and the simulation of machine embroidery techniques through various layout options. Second, in the development of machine embroidery textures, it was found that the setting of the width, height, axis ratio, stitch, object, path, length, density, layer order, etc. in embroidery CAD is a very important part of determining the completeness of the embroidery results. Third, mechanical embroidery textile designs, which can be represented by single-head computer machine embroidery machine were able to show colorful embroidery results that differs from the original image by using seven main techniques and five deep technique alone or in combination, according to the designer's intention.

• 대한방사선기술학회지:방사선기술과학
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• 제38권3호
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• pp.213-220
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• 2015

본 연구는 3차원 입체정위 유방생검술의 정확도를 알아보고, 심부침생검을 이용하여 Stereotactic biopsy과 Sonoguided biopsy의 정확도와 정밀도를 평가하고자 한다. Stereotactic QC phantom을 이용하여 실제 5개의 target 위치로 3D sterotactic machine의 정확도를 측정하고, CT장비로 Scan하여 실측을 구해 X, Y, Z의 길이의 정밀도를 비교한다. 유방조직과 유사하게 제작한 Agar power phantom을 이용하여 5개의 각기 다른 needle tip Target을 통해 3D sterotactic machine과 2D ultrasound machine의 정확도를 비교하고, Z축을 장비별로 실측하여 정밀도와 신뢰도를 비교하며, 6개의 모조병소 Target을 심어놓은 Medical application phantom으로 표적하여 육안검사와 Specimen검사를 통해 정확도를 확인하였다. Stereotactic QC phantom으로 측정한 3D sterotactic machine의 정확도는 100%였으며, CT와 비교한 정밀도는 X, Y, Z축이 모두 p>0.05로 나타났다. Agar powder phantom으로 측정한 두 장비의 정확도는 100%의 정확도를 보였으며, CT와 두 장비 사이에는 p > 0.05로 차이가 없었다. 그러나 2명의 방사선사가 측정한 신뢰도분석에서 3D sterotactic machine은 ICC가 0.954였고, 2D ultrasound machine은 0.785로 2D ultrasound machine이 술자에 따라 차이가 있었다. Medical application phantom의 실험에서 3D sterotactic machine은 Sliced boneless ham을, 2D ultrasound machine은 small chalk powder group를 찾을 수 없었다. Phantom을 이용한 3차원 입체정위 유방생검술의 정확성은 우수하게 나타났고, 인체조직과 비슷한 Agar powder phantom과 유방 조직과 비슷한 Medical application phantom을 이용하여 Stereotactic biopsy과 Sonoguided biopsy의 정확도와 정밀도 모두 우수하게 나타났다. 또한 Medical application phantom의 심부침생검의 정확성 평가에서 각 검사에 따라 생검 표본이 병소의 형태에 따라 상이하게 채취되었고, 3차원 입체정위 유방생검술의 재현성이 유방 초음파검사보다 술자의 영향없이 우수하였다.

• 한국정밀공학회지
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• 제19권2호
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• pp.17-25
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• 2002

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2015년도 춘계학술대회
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• pp.595-597
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• 2015

최근, 전 세계 주요 국가에서 전략산업으로 육성되고 있는 사물인터넷(IoT : Internet of Things) 기술은 사물과 사물간의 소통이 가능한 상황인식 기반의 미래 인터넷 환경이다. 기존의 연구에는 사람이 직접 명령을 내려 디바이스를 제어하는 P2M(Person to Machine) 방식과 단순 센서 데이터를 통한 단일 디바이스 제어방식이 있다. 하지만, IoT의 일종인 Machine Socialization은 각각의 디바이스들이 디바이스 내부 기능정보를 이용하고, Device Manager를 통하여 전체적인 시나리오를 전개하는 M2M(Machine to Machine)방식의 디바이스 협업 시스템이다. 본 논문에서는 기존의 P2M의 시스템을 M2M의 시스템으로 변화시키기 위한 Machine Socialization의 시스템의 알고리즘을 제안한다.

• 정보처리학회논문지A
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• 제14A권3호
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• pp.167-172
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• 2007

가상기계(Virtual Machine)는 소프트웨어로 제작되어 논리적인 시스템 구성을 갖는 컴퓨터이기 때문에 그 수행 속도와 필요 저장 공간 측면에서 성능이 떨어질 수밖에 없다. 이러한 환경에서의 가상기계 코드 최적화는 실행 성능을 향상시킬 수 있기에 중요하다. 특별히 임베디드 장치(Embedded Device)에서 작동하는 가상기계 환경에서의 최적화는 기존의 최적화에 비해 수행 비용 대비 효과에서 높은 효율을 요구한다. 이에 따라 프로파일링을 통하여 성능에 크게 영향을 주는 함수 또는 기본 블록(Basic Block)을 찾아 최적화하는 것이 효과적이다. 본 논문에서는 프로파일링을 이용한 가상기계 코드 최적화기를 설계하고 구현하였다. 먼저, 가상기계 코드 최적화를 위해 코드를 실행하여 얻을 수 있는 동적 정보인 프로파일링 데이터(Profiling Data)를 정의하였고, 프로파일링 정보를 이용한 가상기계 코드 최적기를 구현하였다. 또한, 구현과 실험에 있어서 가상기계 코드는 EVM(Embedded Virtual Machine)의 중간 언어인 SIL(Standard Intermediate Language)를 사용하였고, 구현된 최적화기에 대한 실험을 통해 최적화기의 효과를 확인하였다.

• 치위생과학회지
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• 제20권4호
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• pp.206-212
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• 2020

Background: A Teachable Machine is a kind of machine learning web-based tool for general persons. In this paper, the feasibility of Google's Teachable Machine (ver. 2.0) was studied in the diagnosis of the tooth-marked tongue. Methods: For machine learning of tooth-marked tongue diagnosis, a total of 1,250 tongue images were used on Kaggle's web site. Ninety percent of the images were used for the training data set, and the remaining 10% were used for the test data set. Using Google's Teachable Machine (ver. 2.0), machine learning was performed using separated images. To optimize the machine learning parameters, I measured the diagnosis accuracies according to the value of epoch, batch size, and learning rate. After hyper-parameter tuning, the ROC (receiver operating characteristic) analysis method determined the sensitivity (true positive rate, TPR) and specificity (false positive rate, FPR) of the machine learning model to diagnose the tooth-marked tongue. Results: To evaluate the usefulness of the Teachable Machine in clinical application, I used 634 tooth-marked tongue images and 491 no-marked tongue images for machine learning. When the epoch, batch size, and learning rate as hyper-parameters were 75, 0.0001, and 128, respectively, the accuracy of the tooth-marked tongue's diagnosis was best. The accuracies for the tooth-marked tongue and the no-marked tongue were 92.1% and 72.6%, respectively. And, the sensitivity (TPR) and specificity (FPR) were 0.92 and 0.28, respectively. Conclusion: These results are more accurate than Li's experimental results calculated with convolution neural network. Google's Teachable Machines show good performance by hyper-parameters tuning in the diagnosis of the tooth-marked tongue. We confirmed that the tool is useful for several clinical applications.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2004년도 춘계학술대회 논문집
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• pp.404-409
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• 2004

To maximize the productivity in machining molds and dies, machine tools should operate at high speeds. During the high speed operation of moving frames or spindles, vibration problems are apt to occur if the machine tool structures are made of conventional steel materials with inferior damping characteristics. However, self-excited vibration or chatter is bound to occur during high speed machining when cutting speed exceeds the stability limit of machine tool. Chatter is undesirable because of its adverse effect on surface finish, machining accuracy, and tool life. Furthermore, chatter is a major cause of reducing production rate because, if no remedy can be found, metal removal rates have to be lowered until vibration-free performances is obtained. Also, the resonant vibration of machine tools frequently occurs when operating frequency approaches one of their natural frequencies because machine tools have several natural frequencies due to their many continuous structural elements. However, these vibration problems are closely related to damping characteristics of machine tool structures. The polymer concrete has high potential for machine tool bed due to its good damping characteristics with moderate stiffness. This paper presents the use of polymer concrete and sandwich structures to overcome vibration problems. Also, co-cure bonding method for functional part mounting was exhibited experimentally, by which manufacturing time and cost for polymer concrete bed will be remarkably reduced.