• International conference on construction engineering and project management
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• 2009.05a
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• pp.1468-1473
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• 2009

Efficient communication of construction information has been critical for successful project performance. Building Information Modeling (BIM) has appeared as a tool for efficient communication. Through 3D CAD objects, it is possible to check interception and collisions of each object in advance. In addition, 4D simulation based on 3D objects integrated with time information makes it realize to go over scheduling and to perceive potential errors in scheduling. However, current scheduling simulation is still at a stage of animation due to manual integration of 3D objects and scheduling data. Accordingly, this study aims to develop an integrated model of 3D CAD objects that automatically creates scheduling information.

• Korean Journal of Construction Engineering and Management
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• v.5 no.4 s.20
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• pp.107-114
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• 2004

This paper represents the application of the 3D CAD Model data for 4D simulation and quantity estimation. These support the effective and practical use of 4D CAD model. By using and manipulating the 3D CAD model information, scheduling and quantity estimation could be developed more quickly and effectively. So the 3D CAD model information is made use of not only drawing a blueprint but also playing an important part of data integration platform. The scheduling module sets up the schedule generation logic that consists of period, priority of element arrangement, and time lag of floor placement. It sorts the working items as a priority of working process. And the quantity estimation module queries the material quantity of the structural elements according to the scheduling conditions. These two modules are developed using the 3D CAD model information and assist the function of 4D CAD model.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.30 no.4D
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• pp.413-421
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• 2010

Scheduling management is one of the most important factors for the efficient performance of construction projects. Various computer-aided solutions for schedule management have been developed, but they are not commonly used in practice. This study conducted surveys on scheduling management methods and the related solutions to identify their status and problems in practice. Based on the results of the surveys, this study also developed a scheduling assistant program to improve the usability of scheduling management solutions. Through the developed program, the usability of scheduling management solutions will be improved in practice, thus enabling efficient scheduling management.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38A no.4
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• pp.325-336
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• 2013

FlashLinQ, one of the typical D2D communication systems developed by Qualcomm, considers a single-tone communication based distributed channel-aware link scheduling method to realize the link scheduling process with low control overheads. However, considering the frequency selective fading effect of practical multi-path channel, the single-tone based SIR estimation causes a critical scheduling error problem because the received single-tone signal has quite different channel gain at each sub-carrier location. In order to overcome this problem, we propose a novel link scheduling method based on CAZAC (Constant Amplitude Zero Auto-Correlation) sequence for D2D communication system. In the proposed method, each link has a unique offset value set for the generation of CAZAC sequences. CAZAC sequences with the cyclic offsets are transmitted using multiple sub-blocks in the entire bandwidth, and then each device can obtain nearly full-band SIR using a good cyclic cross-correlation property of CAZAC sequence.

• Journal of Communications and Networks
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• v.6 no.4
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• pp.352-361
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• 2004

In this paper, we study how to achieve the maximum capacity under delay constraints for large mobile wireless networks. We develop a systematic methodology for studying this problem in the asymptotic region when the number of nodes n in the network is large. We first identify a number of key parameters for a large class of scheduling schemes, and investigate the inherent tradeoffs among the capacity, the delay, and these scheduling parameters. Based on these inherent tradeoffs, we are able to compute the upper bound on the maximum per-node capacity of a large mobile wireless network under given delay constraints. Further, in the process of proving the upper bound, we are able to identify the optimal values of the key scheduling parameters. Knowing these optimal values, we can then develop scheduling schemes that achieve the upper bound up to some logarithmic factor, which suggests that our upper bound is fairly tight. We have applied this methodology to both the i.i.d. mobility model and the random way-point mobility model. In both cases, our methodology allows us to develop new scheduling schemes that can achieve larger capacity than previous proposals under the same delay constraints. In particular, for the i.i.d. mobility model, our scheme can achieve (n-1/3/log3/2 n) per-node capacity with constant delay. This demonstrates that, under the i.i.d. mobility model, mobility increases the capacity even with constant delays. Our methodology can also be extended to incorporate additional scheduling constraints.

• ETRI Journal
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• v.33 no.5
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• pp.689-694
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• 2011

In this paper, we study scheduling schemes for two-user two-way wireless relaying systems. Two transmission modes are considered: point-to-point direct transmission and two-way amplify-and-forward relaying. An optimal scheduling scheme that opportunistically selects the best transmission mode for each user is proposed to minimize the sum bit error rate (BER). The performance lower bound of the optimal scheduling scheme is analyzed, and closed-form expression of the lower-bound BER is derived. However, for optimal scheduling, the scheduler requires the knowledge of channel state information (CSI) of all links. To reduce the feedback information of CSI, we also propose a suboptimal scheduling scheme that selects the transmission mode using only the CSI of two direct links. Simulation results show that there are 4 dB to 8 dB gains for the proposed optimal and suboptimal schemes over the fixed direct transmission and fixed two-way relayed transmission scheme. The performance gap between the optimal and suboptimal scheduling schemes is small, which implies a good trade-off between implementation complexity and system performance.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.4
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• pp.692-699
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• 2008

Semiconductor research and development(R&D) fabs are very different than production fabs in many ways such as the scales of production, job priority, production methods, and performance measures. Efficient operations of R&D fabs are very important to the development of new product, process stability, high yield, and ultimately company competitiveness. This paper proposes the fab-wide scheduling method for operational optimization of the R&D fabs. Most scheduling systems of semiconductor fabs have only focused on maximizing throughput of each separated areas without considering WIP(works in process) flows of entire fab. In this paper, we proposes the a fab-wide scheduling system which schedules all lots to entire fab equipment at once. We develop the MIP(mixed integer programing) model which allocates the lots to production equipment considering many constraints of all processes and the CP(constraint programming) model which determines the sequences of the lots in the production equipment. The proposed FAB-wide scheduling model is applied to the newly constructed R&D fab. As a result, we have accomplished the system based automated job reservation, decrease of the hot lot delay, increase of the queue time satisfaction, the high throughput by maximizing the batch sizes, decrease of the WIP TAT(Turn Around Time).

• The KIPS Transactions:PartA
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• v.14A no.4
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• pp.197-202
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• 2007

This study focused on design and implementation of Mobile 3D Bluetooth Game Engine based on OpenGL-ES. In Mobile 3D network game so far, there is a form the mainstream of wireless inter-net game using WAP and VM. But, VM game we popular because of an excessive communication expense problem for this mobile network game that occur when connect to wireless internet as point out to problem by it, that is, stand-alone game are very popular. This study introduce a mobile 3D Bluetooth Game Engine which is based on mobile 3D standard using OpenGL-ES to solve a problem like mobile network game generally that occur when connect to take pleasure a wireless internet from some people into a short distance. When the number of concurrent packet datum by Bluetooth terminal transfers to each other, we shows that the proposed scheduling scheme for enhancing the process speed up on Bluetooth.

• IEMEK Journal of Embedded Systems and Applications
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• v.7 no.1
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• pp.9-15
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• 2012

Recently, as the development of 3D contents service, production of 4D media that user can feel physical effects by the scene of movie has been increased. This 4D media uses the SMMD (Single Media Multiple Devices) method to give users enhanced effects with multiple devices playing rather than the SMSD (Single Media Single Device) method with single device playing in a smart TV environment. To give more sensible effects to users, from the beginning of making one media, we produced 4D media that consists of 3D contents and the SEM (Sensory Effect Metadata) to define effects of the scene. 4D media is transmitted to a HS (Home Server) to represent 3D contents in 3DTV and multiple devices with synchronized way. In this paper, we suggested the concept and overall 4D media broadcasting service system architecture, aggregator time acquisition, media time scheduling, real-sense device scheduling, evaluation results, user interfaces and implemented devices.

• Journal of Communications and Networks
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• v.12 no.4
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• pp.346-357
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• 2010

Opportunistic scheduling provides the capability of resource management in wireless networks by taking advantage of multiuser diversity and by allowing delay variation in delivering data packets. It generally aims to maximize system throughput or guarantee fairness and quality of service (QoS) requirements. In this paper, we develop an extended proportional fair (PF) scheduling policy that can statistically guarantee three kinds of QoS. The scheduling policy is derived by solving the optimization problems in an ideal system according to QoS constraints. We prove that the practical version of the scheduling policy is optimal in opportunistic scheduling systems. As each scheduling policy has some parameters, we also consider practical parameter adaptation algorithms that require low implementation complexity and show their convergences mathematically. Through simulations, we confirm that our proposed schedulers show good fairness performance in addition to guaranteeing each user's QoS requirements.