• Journal of Construction Engineering and Project Management
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• v.5 no.2
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• pp.11-15
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• 2015

The Last PlannerSystem (LPS) has been implemented on construction projects to increase work flow reliability, a precondition for project performance againstproductivity and progress targets. The LPS encompasses four tiers of planning processes:master scheduling, phase scheduling, lookahead planning, and commitment / weeklywork planning. This research highlights deficiencies in the current implementation of LPS including poor lookahead planning which results in poor linkage between weeklywork plans and the master schedule. This poor linkage undetermines the ability of theweekly work planning process to select for execution tasks that are critical to projectsuccess. As a result, percent plan complete (PPC) becomes a weak indicator of project progress. The purpose of this research is to improve lookahead planning (the bridgebetween weekly work planning and master scheduling), improve PPC, and improve theselection of tasks that are critical to project success by increasing the link betweenShould, Can, Will, and Did (components of the LPS), thereby rendering PPC a betterindicator of project progress. The research employs the case study research method to describe deficiencies inthe current implementation of the LPS and suggest guidelines for a better application ofLPS in general and lookahead planning in particular. It then introduces an analyticalsimulation model to analyze the lookahead planning process. This is done by examining the impact on PPC of increasing two lookahead planning performance metrics: tasksanticipated (TA) and tasks made ready (TMR). Finally, the research investigates theimportance of the lookahead planning functions: identification and removal ofconstraints, task breakdown, and operations design.The research findings confirm the positive impact of improving lookaheadplanning (i.e., TA and TMR) on PPC. It also recognizes the need to perform lookaheadplanning differently for three types of work involving different levels of uncertainty:stable work, medium uncertainty work, and highly emergent work.The research confirms the LPS rules for practice and specifically the need to planin greater detail as time gets closer to performing the work. It highlights the role of LPSas a production system that incorporates deliberate planning (predetermined andoptimized) and situated planning (flexible and adaptive). Finally, the research presents recommendations for production planningimprovements in three areas: process related, (suggesting guidelines for practice),technical, (highlighting issues with current software programs and advocating theinclusion of collaborative planning capability), and organizational improvements(suggesting transitional steps when applying the LPS).

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2012.10a
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• pp.3-6
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• 2012

Due to recent rapid growth of mobile market, the modern people increasing make use of mobile contents as a means to obtain the desired information quickly by overcoming various restraints of a computer. The wide range of recommended contents, however, takes much time in selection of contents. To resolve such issues, a system that predicts the contents desired by the user and makes an accurate recommendation is necessary. In this paper, in order to provide the desired contents in line with the user demands, a method to increase select the number of recommendation using cooperative filtering is proposed. In the first step, the categories are formulated with super-classes and the similarity between the target customer and users is found, and the nearest-neighbors are constituted to find the preference predictions between super-classes, and the super-class with the highest resulting value is recommended to the target customer. In the second step, the preference predictions between sub-classes are found and the sub-class with the highest value is recommended to the target customer. In the experiment, mobile contents are recommended through super-class-based cooperative filtering, and then the mobile contents are recommended through sub-class-based cooperative filtering, and sub-class collaborative filtering method to select a high number of verification.

• Journal of Information Technology Applications and Management
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• v.25 no.1
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• pp.1-17
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• 2018

This study presents a research model that demonstrates the dominant design technology strategy for developing and securing dominant design technology based on open innovation. For this purpose, this study developed a strategic model for the development and acquisition of design technology, production technology, and production system of propeller which satisfies the requirements of ship propulsion system required by ship owners and shipbuilders. By studying large propellers for ships, it is possible to embody a strategic model that can be used as a technology development strategy of dominant design that is effective in technology field of other industries. In this study, HSP (High Skewed Propeller) strategy of Hyundai Heavy Industries, which occupies the largest global market share (47.5%, 2007) for more than 30 years until now, is analyzed as a successful case to verify this strategic model. The development and acquisition strategy model of dominant design technology presented in this study consists of four stages : dominant design project strategy, dominant design engineering technology strategy, dominant design production technology strategy, and dominant design production system strategy. The strategic model summarizes the key activities at each stage. In addition, the steps and core activities of this strategic model were confirmed through the case study. As a technology development strategy of HSP products, Hyundai Heavy Industries utilized open innovation technology to cooperate with outside, that is, collaborative research and development with KAIST (Korea Advanced Institute of Science and Technology) research team, and succeeded in achieving technology development of dominant design of HSP products by linking it with HSP technology development and acquisition strategy.

• Journal of the Korea Society for Simulation
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• v.27 no.3
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• pp.1-11
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• 2018

Discrete event system specification (DEVS) has been used in many simulations including hybrid systems featuring both discrete and continuous behavior that require a lot of time to get results. Therefore, in this study, we proposed the acceleration of a DEVS-based hybrid system simulation using multi-cores and GPUs tightly coupled computing. We analyzed the proposed heterogeneous computing of the simulation in terms of the configuration of the target device, changing simulation parameters, and power consumption for efficient simulation. The result revealed that the proposed architecture offers an advantage for high-performance simulation in terms of execution time, although more power consumption is required. With these results, we discovered that our approach is applicable in hybrid system simulation, and we demonstrated the possibility of optimized hardware distribution in terms of power consumption versus execution time via experiments in the proposed architecture.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.14 no.2
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• pp.671-686
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• 2020

Due to the long training time and high training cost of traditional surgical training methods, the emerging virtual surgical training method has gradually replaced it as the mainstream. However, the virtual surgical system suffers from poor authenticity and high computational cost problems. For overcoming the deficiency of these problems, we propose an optimized model for the local compression deformation of soft tissue. This model uses a simulated annealing algorithm to optimize the parameters of the soft tissue model to improve the authenticity of the simulation. Meanwhile, although the soft tissue deformation is divided into local deformation region and non-deformation region, our proposed model only needs to calculate and update the deformation region, which can improve the simulation real-time performance. Besides, we define a compensation strategy for the "superelastic" effect which often occurs with the mass-spring model. To verify the validity of the model, we carry out a compression simulation experiment of abdomen and human foot and compare it with other models. The experimental results indicate the proposed model is realistic and effective in soft tissue compression simulation, and it outperforms other models in accuracy and real-time performance.

• Transactions of the Korean Society of Automotive Engineers
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• v.20 no.4
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• pp.109-118
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• 2012

Large number of part design for aircraft and automobile is preceded by functional or sectional design groups for efficiency. However, interferences and gaps can be found when the parts and sub-assemblies by those design groups are to be assembled. These interferences and gaps cause design changes and additional repair processes. While interference problem has been resolved by digital mockup and concurrent engineering methodology, gap problem has been covered by temporary treatment of filling gap with sealant. This kind of fast fix causes fatal problem of leakage when the gap is too big for filling or the treatment gets old. With this research, we have developed a program to find the gap automatically among parts of assembly so that users can find them to correct their design before manufacturing stage. By using decomposition model representation method, the developed program can search the gap among complex car body parts to be visualized with volumetric information. It can also define the boundary between the gap and exterior empty space automatically. Though we have proved the efficiency of the developed program by applying to automobile assembly, application of the program is not limited to car body only, but also can be extended to aircraft and ship design of large number of parts.

• Proceedings of the Korean Information Science Society Conference
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• 2005.07a
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• pp.652-654
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• 2005

WebDAV는 웹통신 프로토콜인 HTTP/1.1의 확장으로서 인터넷을 통하여 다양한 자원의 비동기적인 협업을 지원하는 표준 프로토콜이다. CoSlide 시스템은 협업을 효과적으로 지원하기 위하여 WebDAV 프로토콜을 확장하여 개발된 협업시스템이다. CoSlide 협업시스템은 협업을 위한 가상공간을 제공하며 가상공간에 다양한 자원을 등록 및 관리할 수 있다. CoSlide 협업시스템을 활용하여 효과적인 협업을 수행하기 위한 사용자 중심의 클라이언트가 필요하다. 본 논문에서는 WebDAV 프로토콜을 이용한 협업시스템인 Coslide를 효과적으로 활용하기 위한 클라이언트 개발에 대하여 기술한다. 개발된 클라이언트는 사용자가 서버에 등록한 자원을 관리하는 기능과 팀원들 간의 상호 작용을 원활하게 지원하는 사용자 인터페이스를 제공한다. 또한 CoSlide 협업시스템을 사용하는 사용자는 새로운 작업장을 생성하고 다른 사용자를 초대할 수 있으며, 작업장에 파일을 등륵, 이동 그리고 삭제할 수 있다. 기존의 협업시스템에서 분산저작을 하는 경우 클라이언트에서 제공하는 특정 프로그램을 이용하거나, 파일을 서버로부터 내려받아 이를 수정하여 다시 등록하는 과정을 거친다. 본 클라이언트는 이러한 단점을 개선하여 CoSlide 협업시스템의 자원에 대하여 다양한 저작프로그램을 자동적으로 연결하여주며, 실시간으로 협업시스템의 자원을 갱신하여 준다. 또한 자원에 대한 일관성을 보장하기 위하여 자동 잠금기능을 제공한다. 추가적으로 사용자는 드래그앤드랍 기능을 이용하여 작업장간의 자원을 이동할 수 있다.

• The Journal of Society for e-Business Studies
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• v.18 no.4
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• pp.45-65
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• 2013

A design file can get larger in size as the complexity of the target object increases. A large design file may reside in a large parallel computing system, such as cloud computing systems, and many designers may work concurrently on the same design file. In such a case, it is obvious that we need some kind of protection mechanism so that each user can access only the area of the file he or she is entitled to. Two approaches can be taken for this problem: one is the traditional access control mechanisms and the other encryption techniques. We take the latter approach to ensure the safety of the file even in public domain such as clouding systems, and in this paper, we suggest an encryption scheme for a file where the file is encrypted in multi-layer so that each user is allowed to access the file only at the layer for which the user has the proper access right. Each layer of the file is encrypted with different keys and these keys are exposed only to those who have the right access permit. The paper explains the necessary file format to achieve this goal and discusses the file manipulation functions to handle this new file format.

• ETRI Journal
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• v.42 no.5
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• pp.669-685
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• 2020

5G AgiLe and fLexible integration of SaTellite And cellulaR (5G-ALLSTAR) is a Korea-Europe (KR-EU) collaborative project for developing multi-connectivity (MC) technologies that integrate cellular and satellite networks to provide seamless, reliable, and ubiquitous broadband communication services and improve service continuity for 5G and beyond. The main scope of this project entails the prototype development of a millimeter-wave 5G New Radio (NR)-based cellular system, an investigation of the feasibility of an NR-based satellite system and its integration with cellular systems, and a study of spectrum sharing and interference management techniques for MC. This article reviews recent research activities and presents preliminary results and a plan for the proof of concept (PoC) of three representative use cases (UCs) and one joint KR-EU UC. The feasibility of each UC and superiority of the developed technologies will be validated with key performance indicators using corresponding PoC platforms. The final achievements of the project are expected to eventually contribute to the technical evolution of 5G, which will pave the road for next-generation communications.

• Journal of the Korea Society of Computer and Information
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• v.16 no.7
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• pp.127-135
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• 2011

It is required that an e-learning system has a content recommendation component which helps a learner choose an item. In order to predict items concerning learner's interest, collaborative filtering and content-based filtering methods have been most widely used. The methods recommend items for a learner based on other learner's interests without considering the knowledge level of the learner. So, the effectiveness of the recommendation can be reduced when the number of overall users are relatively small. Also, it is not easy to recommend a newly added item. In order to address the problem, we propose a content recommendation method based on the similarity and the difficulty of an item. By using a recommendation function that reflects both characteristics of items, a higher-level leaner can choose more difficult but less similar items, while a lower-level learner can select less difficult but more similar items, Thus, a learner can be presented items according to his or her level of achievement, which is irrelevant to other learner's interest.