• Journal of the Korea Society of Computer and Information
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• v.16 no.4
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• pp.119-126
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• 2011

When ZigBee network supports beacon transmission mechanism, ZigBee devices have the restriction of the transmission range from the coordinator. On the contrary, when it does not support beacon transmission, it is not easy to save the energy through turning into sleep mode. This paper proposes active slot allocation method that allocates a transmission time and does not use the beacon transmission mechanism. It is based on the ZigBee's distributed address assignment mechanism and supports the scalability. This paper explains the active slot structure and the allocation order and describes the operation of ZigBee devices. We verify the proposed mechanism through the simulation and show the performance evaluation. It can be useful on the industrial automation and the environmental surveillance.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.9 no.6
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• pp.151-158
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• 2010

In line with the requirement of appropriate protocol support for such mission-critical wireless sensor network (WSN) applications as patient monitoring, we investigate the framework for designing medium access control (MAC) schemes. The data traffic in medical systems comes with inherent traffic heterogeneity as well as strict requirement of reliability according to the varied extents of devise-wise criticality in separate cases. This implies that the quality-of-Service (QoS) issues are very distinctly delicate requiring specialized consideration. Besides, there are features in such systems that can be exploited during the design of a MAC scheme. In a monitoring or routine surveillance application, there are degrees of regularity or predictability in traffic as coordinated from a node of central control. The coordinator thus takes on the role of marshaling the resources in a neighborhood of nodes deployed mostly for upstream traffic; in a collision-free scheme, it schedules the time slots for each superframe based on the QoS specifications. In this preliminary study, we identify the key artifacts of such a MAC scheme. We also present basic performance issues like the impact of superframe length on delay incurred, energy efficiency achieved in the network operation as obtained in a typical simulation setup based on this framework.

• Korean Institute of Interior Design Journal
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• v.13 no.5
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• pp.223-229
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• 2004

The investment scale of design project has been increased rapidly following the recent social and economical demand. The demand of user has been changed variously together with social background like the increase of interest for the high level information oriented society and environment. In addition, it is necessary for the experts like coordinator, architect, color expert, and light designer to collaborate in the interior design process. The expertise diverse areas should be related closely and collaboratively for the smooth processing. It is necessary for the design environment to be changed in order to exchange the information effectively within the proposed period by the variety fields' experts. It is a collaborative design in the design studio that the multi-members collect the related data, suggest the idea, and discuss closely, which makes a decision for the new design concept and design plan in the fixed time. It is necessary to make a new kind of communication media concept in the design process, where the multi-members participate, and the collaborative design is processed in physically simultaneous space or in the far distance such as it is done above. In this paper, it is investigated for the communication for the design and creative behavior to explain the collaborative work in the process of design. The characteristics of collaborative design and demand design environment are summarized in the background of this kind of the creative behavior concept. Especially, the communication media for increasing the process effectiveness is explained and the concept for the development of web based collaborative design system is summarized.

• Journal of Internet of Things and Convergence
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• v.6 no.3
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• pp.7-13
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• 2020

In this paper, we propose a system that monitors and controls the environment of a server room in real-time based on IoT. Recently, as the information society has been maximized, the damage has been significant when the computer system is down. In particular, damage such as a fire in the server room leads to loss of data and data recovery becomes impossible. In order to reduce such damage, a node capable of real-time monitoring using an IoT system was proposed. In addition, we proposed a coordinator node that can collect and monitor node information. In order to verify that the proposed system works, we have developed software that can control node monitoring and air conditioning. As a result of the experiment, we confirmed that the proposed system detects fire and controls the air conditioner.

• Korean Journal of Construction Engineering and Management
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• v.5 no.3 s.19
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• pp.55-62
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• 2004

The purpose of this study is to suggest a systematic procedural model for selecting competent project promoter. The proposed model was made by comparing domestic regulations and procedures with foreign nations', and through interviews with experts and literatures survey. The summaries of this paper are as follows. The current promoter selection procedure was evaluated by reviewing relevant papers, regulations and existing model. Some obstructions which hinder PPI project activation were identified, those are inadequacy of promoter qualification and negotiation process, lack of communication between parties, etc. Some alternatives which remove major obstructions are embodied in the model. The suggested model is comprised of PQ(prequalification), two phased evaluation for the technical proposals which include alternate, communication meeting, etc. To manage the overall procedure well, an involvement of professional "project promoter selection team" would be highly recommended. They will participate in each evaluation stage with full activities, and provide government with some technical materials for selecting promoter as coordinator.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.9A
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• pp.837-843
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• 2006

IEEE802.15.3 and IEEE802.15.4 have defined the hybrid MAC protocols based on TDMA and CSMA where a multi-frame TDMA structure is employed so that multiple data frames can be transmitted within one timeslot to guarantee minimum delay bounds of isochroous traffic. However, TDMA has an intrinsic problem that cannot dynamically allocate optimal length of timeslot to each station. Therefore the idle timeslot can be produced by stations when each transmission queue is instantaneously empty during its timeslot, which would waste lots of timeslots especially in the multi-frame TDMA systems. In this paper, we propose a more flexible multiple-access scheme for the multi-frame TDMA system based on the concept of virtual slot which is accessible by every station with the highest priority for slot owner and lower priority for other stations. Finally, our simulation results from various environments show that proposed scheme can achieve magnitude improvement of total system throughput and average message delay by maximizing channel utilization.

• Journal of KIISE:Computing Practices and Letters
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• v.14 no.4
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• pp.436-440
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• 2008

In IEEE 802.15.4 beacon-enabled mode, performance decreases as the number of devices competing in the contention access period(CAP) increases. In this letter, we propose partitioned contention access mechanism(PCAM) to compensate performance degradation. In PCAM, the PAN coordinator divides CAP into two sub-periods and activity of devices is delimited in their assigned sub-periods. Since PCAM reduces the number of devices which compete at the same time by half, collision probability between transmitted frames can be reduced. In addition, devices can save their power consumption because PCAM shorten the duration that devices stay in active state into half. We perform simulations to compare the performance of PCAM with that of the IEEE 802.15.4 standard. From the result, PCAM yields better performance than IEEE 802.15.4 standard.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.05a
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• pp.177-178
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• 2006

Many authors issued the feature-preserving averaging technique according to positioning and scaling process using landmarks, which represent the geometric characteristics of three dimensional surface models. Such a technique should be done by manual procedure, choosing and marking the landmarks on each bone surface before averaging process. In this study, we produced another averaging technique without having to use such manual procedure, and made averaging models from three dimensional surface data that were reconstructed from computerized tomography images of Digital Korean Project. The bone models were subjected to orthogonal coordinator system. These models were transformed to coincide mass center and to align principal axis. Then, bone models were scaled according to average length data of sample bone models on all axis(x, y, z). After establishing voxellar hexahedron space which contain all sample bone models, we counted the number of overlapping for each voxel. We generated the three dimensional average surface by displaying the yokels that have more overlapping number than boundary number. The boundary number was decided when the average volume of each bone equal to the volume of bone that would be averaged. Using this technique, we can make a feature-preserving averaging volume of bones.

• Land and Housing Review
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• v.7 no.2
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• pp.103-111
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• 2016

The paradigm of the housing policy has been transformed from housing supply to housing welfare, from the policy of housing quantity expansion to the policy of customized housing welfare. The Housing Act was newly enacted to realize the new paradigm of the housing policy. The Act establishes the role of the Housing Welfare Centers in the housing welfare delivery system, but they have some difficulties in doing their role because of limited amount of centers and their manpower. The desirable and efficient model of housing welfare delivery system, therefore, is that the demand of housing welfare is discovered on local base, and that demanders can be provided housing welfare service connected to local governments or neighborhood housing welfare centers. To do so local communities should be established and activated, and the needs of housing welfare service also be discovered. This study is a exploratory one on communities' role in housing welfare delivery system in spite of some limitations based on existing theories and studies, and is significant as a new trial.

• Journal of Fashion Business
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• v.20 no.2
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• pp.165-180
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• 2016

Capstone design, is a heartfelt cooperation curriculum because the ultimate goal is to train people who already have the ability to complete the tasks of the job without retraining them in the field immediately after being hired. However, there is a need for the design study in the fashion industry where a variety of operating models could be tried; more specifically case studies than engineering. This study was designed to apply to the types of voluntary projects and industrial challenges linked to the different types of virtuous circle window systems over twice in two years. Result capitalization applied to different types of derived forms associated with start-up technology transfer form. In addition, start-up will be done in conjunction with student-centered forms of the participation of Cooperation Coordinator. This was weak in the form of technology transfer interventions which were made as a result of the overall involvement of the industry. In order to elicit the active participation of the industry it is expected that this system will have an ideal company to reflux. Therefore, reflux that created assets to the students, and the reflux of product design created by students in companies professor final a virtuous cycle system operating models that can derive enhancements accept feedback to both students and companies redefining the performing models It presented. This operating model is considered to be able to provide you with a sense of accomplishment and high experiential value to both students and professors, and the industry. In this study, experiments in environmental A Study, silseupbi no support will be given to alternatives to solve them.