• Title/Summary/Keyword: LOM

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Dimensional Error Analysis of Products from LOM Process (LOM 공정에서의 제품 치수 오차 분석에 관한 연구)

  • 하성도;김경환;송용억;박태권;김창희
    • Journal of the Korean Society for Precision Engineering
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    • v.15 no.12
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    • pp.89-96
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    • 1998
  • LOM (Laminated Object Manufacturing) process is one of rapid prototyping processes, where shapes are formed by accumulating cross sections of laser-cut paper. The process expects wide popularity since it is simple and the material is familiar to conventional mockup makers. However the dimensional accuracy of LOM parts is not so good as that of traditional wooden mockups, since the stack of adhesive-spread papers causes significant dimensional error. Also it is unclear how the other unknown environmental effects cause the errors as well. In this work the dimensional errors of LOM parts are measured and analysed. Experiments with test parts were performed in order to see the effects of part shape, moist, and sealer on dimensional variations. The characteristic of the paper is also analysed. Re-heating LOM parts, which is shown to have the effect of recovering dimensional changes, is applied to an example part.

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Development of Method for Manufacturing Freeform EPS Forms Using Sloped-LOM Type 3D Printer (Sloped-LOM 방식 3D 프린터를 이용한 비정형 EPS 거푸집 제작 공법 개발)

  • Ahn, Heejae;Lee, Dongyoun;Ji, Woojong;Lee, Woojae;Cho, Hunhee
    • Journal of the Korea Institute of Building Construction
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    • v.20 no.2
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    • pp.171-181
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    • 2020
  • Recently, free-formed construction technology is becoming a new measure of representing technological superiority and sociocultural ingenuity. However, the CNC processing technology utilizing the existing wood and iron form has limitations in terms of the manufacturing time and material cost. Therefore, in this study, the method and process of manufacturing free-formed EPS form using S-LOM-based 3D printing technology were suggested. Furthermore, through the mock-up test, a comparative analysis of the manufacturing time and precision with CNC milling technology was conducted. The results show that S-LOM-based 3D printing technology has reduced manufacturing time about 57.4% compared to CNC milling technology during the free-formed EPS form manufacturing process. In addition, compared to the design drawings, the maximum error value was 20.5mm, proving the applicability of S-LOM-based 3D printing technology. The results of this study are expected to contribute to the improvement of S-LOM method and the activation of S-LOM method by verifying the applicability of S-LOM-based 3D printing technology.

A Study on Manufacturing Process of Pattern with LOM System (LOM 시스템을 이용한 패턴제작에 관한 연구)

  • Choi, Man-Sung;Choi, Bae-Ho
    • Journal of the Korean Society for Precision Engineering
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    • v.18 no.3
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    • pp.47-52
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    • 2001
  • Rapid Prototyping(RP) has been widely applied in designing and developing process of new products. RP can reduce the lead time and expense required to bring a new product form initial concept to production. Among several RP process can dramatically reduce the total build time and be applied for fabrication of large-sized and free form object because it uses in LOM the paper thickness is 0.05∼0.38mm as deposition feature segment. In this study, mechanical properties of pattern with LOM system is studied for optimal design of sand mold casting. The main result is that tensile, compressive strength and pattern size are significantly affected by temperature of hot roll.

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A Study on the Design and Implementation of the Lightweight Object Model Supporting Distributed Trader (분산 트레이더를 지원하는 경량 (lightweight) 객체 모델 설계 및 구현 방안 연구)

  • Jin, Myeong-Suk;Song, Byeong-Gwon
    • The Transactions of the Korea Information Processing Society
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    • v.7 no.4
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    • pp.1050-1061
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    • 2000
  • This paper presents a new object model, LOM(Lightweight Object Model) and an implementation method for the distributed trader in heterogeneous distributed computing environment including mobile network. Trader is third party object that enables clients to find suitable servers, which provide the most appropriate services to client in distributed environment including dynamic reconfiguration of services and servers. Trading service requires simpler and more specific object model than genetic object models which provide richer multimedia data types and semantic characteristics with complex data structures. LOM supports a new reference attribute type instead of the relationship, inheritance and composite attribute types of the general object oriented models and so LOM has simple data structures. Also in LOM, the modelling step includes specifying of the information about users and the access right to objects for security in the mobile environment and development of the distributed storage for trading service. Also, we propose and implementation method of the distributed trader, which integrates the LOM-information object model and the OMG (object Management Group) computational object model.

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Representation and Management of e-Learning Object Metadata Using ebXML (ebXML 등록저장소를 이용한 이러닝 객체 메타데이터의 표현과 관리)

  • Kim, Hyoung-Do
    • The Journal of the Korea Contents Association
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    • v.6 no.11
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    • pp.249-259
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    • 2006
  • E-learning objects should be appropriately described and classified using standard metadata for facilitating the processes of e-learning resource description, discovery and reuse. These metadata need to be published in a registry to reduce duplication of effort and enhance semantic interoperability. This paper describes how standard ebXML registries can be used for annotating, storing, discovering and retrieving e-learning object metadata. For semantic annotation of e-learning objects, IEEE LOM is adopted as the metadata ontology. In order to support the e-learning metadata ontology in interoperable ebXML registries, a mapping scheme between LOM and ebXML information model is proposed. The usefulness of standard ebXML registries for sharing e-learning metadata is demonstrated by prototyping an e-learning registry called ebRR4LOM based on the scheme.

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Three Clinical Cases on Acute Lumbar Sprain Patients with Limited Range of Motion by Chuna Treatment (Saban-Method Technique) and Oriental Medical Treatments (관절 가동범위 제한을 동반한 급성 요추부 염좌 환자에 요부사반법(腰部斜搬法)과 한방치료를 병행한 치험 3례)

  • Lee, Kyung-Moo;Ahn, Hee-Bin;Lim, Sang-Hoon;Kim, Soon-Joong;Jeong, Su-Hyeon
    • Journal of Korean Medicine Rehabilitation
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    • v.19 no.4
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    • pp.189-202
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    • 2009
  • Objectives : This study was performed to evaluate the effects of Chuna treatment (Saban-method technique) on acute lumbar sprain patients with limited range of motion(LOM). Methods : Three patients suffered from acute lumbar sprain with LOM, were treated with Chuna therapy(Saban-method technique), acupuncture, herbal medicine, physical therapy and measured by VAS(Visual Analogue Scale) and ODI(Oswestry Disability Index). Results : After Chuna treatment and oriental medical treatments, we found out a recovery from three patients suffering from acute low back pain with LOM. Conclusions : Through this study, we suggest that Chuna treatment(Saban-method technique) and oriental medical treatments was effective to cure acute lumbar sprain patient with LOM.

Development of Productivity Analysis Simulation Model for Formwork Based on 3D Printing Technology Using ARENA (ARENA를 활용한 3D 프린팅 기술 기반 거푸집 공사의 생산성 분석 시뮬레이션 모델 개발)

  • Ahn, Heejae;Lee, Changsu;Kim, Harim;Kim, Taehoon;Cho, Hunhee;Kang, Kyung-In
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2021.11a
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    • pp.188-189
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    • 2021
  • The technology of manufacturing freeform molds with S-LOM based 3D printer has advantages in the production period and the curvature range. However, there is no any support tool about productivity analysis of S-LOM technology because S-LOM technology is early-stage technology. There can be problems about increase of construction time and cost without any decision support tool like productivity analysis models etc. Therefore, in this study, the productivity analysis simulation model for freeform formwork based on S-LOM technology was developed using ARENA software. The process and logic of manufacturing freeform molds can be easily visualized in this model. Futhermore, the resource like labor, equipment and material can be easily optimized with this model. As a result, it can contribute to preventing the increase of construction time and cost in formwork with further productivity analysis.

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Stiff Knee Following Anterior Cruciate Ligament Reconstruction - Cause Analysis and Treatment - (전방 십자 인대 수술 후 합병된 슬관절 강직 - 원인분석 및 치료 -)

  • Choi, Nam Yong;Lee, In Ju;Choi, Moon Ku;Ko, Hae Sok;Kim, Seung Ki;Park, Sung Jin;Han, Suk Koo;Kang, Young Mok
    • Journal of the Korean Arthroscopy Society
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    • v.2 no.1
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    • pp.72-76
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    • 1998
  • Between March 1992 and December 1995 at St. Paul's, Holy Family, St. Vincent and Eui Jung Bu St. Mary Hospitals Catholic University, two hundred and eighty patients underwent arthroscopic anterior cruciate ligament(ACL) reconstruction using central one-third bone-patellar tendon-bone autograft. Nine of these patients had limitation of motion(LOM) defined as a knee flexion contracture greater than 10o or less than 125o of passive knee flexion. This study analyzes the causes of LOM after ACL reconstruction as well as the results after passive manipulation or arthroscopic adhesiolysis under anesthesia for LOM. The results are as follows: 1. Out of nine patients, initially three had isolated ACL injuries and six had combined injuries. Seven of nine cases were perfomed by ACL reconstruction within four weeks and two were performed after four weeks following injury. 2. Treatment for LOM after ACL reconstruction was done after 5.5 months on average. 3. Arthroscopic adhesiolysis was done in 5 cases. There were fibrous adhesions at suprapatellar pouch and femoral intercondylar notch in all cases, respectively, infrapatellar fat pad in 3 cases and medial para patellar gutter in 2 cases. Two patients had a fibrous nodule, "cyclops" lesion, which formed anterior to the ACL graft. 4. Range of motion and Lysholm knee score were much improved following passive manipulation or arthroscopic adhesiolysis under anesthesia for LOM.

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Development of a Loss of Mains Detection Method for Distributed Resources (분산 전원의 고립 운전 검출 기법 개발)

  • Jang, S.I.;Kim, K.H.
    • Proceedings of the KIEE Conference
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    • 2001.05a
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    • pp.42-45
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    • 2001
  • The islanding protection for distributed resources (DR) becomes an important and emerging issue in power system protection since the distributed generator installations are rapidly increasing and most of the installed systems are interconnected with distribution network. In order to avoid the negative impacts on distributed network resulting from islanding operations of DR, it is necessary to detect the loss of mains (LOM) effectively. This paper presents a new LOM detection method using the rate of change in total harmonic distortion (THD) of current. The proposed method effectively detects LOM of the DR unit operating in parallel with the distribution network. We also verified the efficiency of the proposed method using the radial distribution network of IEEE 34 bus model.

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