• Industrial Engineering and Management Systems
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• v.7 no.1
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• pp.57-65
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• 2008

Available-to-promise (ATP) exhibiting availability of manufacturing resources can be used to support customer order promising. Recently, one advanced function called Capable-to-promise (CTP) is provided by several modern APS (advanced planning system) that checks available capacity for placing new production orders or increasing already scheduled production orders. At the customer enquiry stage while considering the order delivery date and quantity to quote, both ATP and CTP are allocated to support order promising. In particular, current trends of mass customization and multi-side production chain derive several new constraints that should be considered when ATP/CTP allocation planning for order promising - such as customer's preference plants or material vendors, material compatibility, etc. Moreover, ATP/CTP allocation planning would be executed over a rolling time horizon. To utilize capacity and material manufacturing resource flexibly and fulfill more customer orders, ATP/CTP rolling planning should possess resource reallocation mechanism under the constraints of order quantities and delivery dates for all previous order promising. Therefore, to enhance order promising with reliability and flexibility to reallocate manufacturing resource, the ATP/CTP reallocation planning mechanism is needed in order to reallocate material and capacity resource for fulfilling all previous promised and new customer orders beneficially with considering new derived material and capacity constraints.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.8 no.3
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• pp.586-597
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• 2004

MAC (Medium Access Control) protocol is necessary for a OLT (Optical Line Termination) to allocate bandwidth to ONUs (Optical Network Units) dynamically in ATM PON (Passive Optical Network) operated in a kind of optical subscriber network having tree topology. The OLT collect information about ONUs and provide all permission with each ONU effectively by means of MAC protocol. Major functions of MAC protocol are composed of the algorism for distributing permission demanded by a ONU dynamically and allocation all permission used in APON properly. Sometimes MAC get to be a element of limiting the whole operation speed and occupy a most frequent operation part of the TC (Transmission Convergence) function module so it have to be designed to guarantee the best quality for each traffic. This paper introduce the way of implementation of a algorism which satisfy all of the upper renditions. This MAC algorism allocate bandwidth according to a number of working ONU and the information of the queue length dynamically and distribute permission for same interval to minimize delay variation of each ONU cell. MAC scheduler for the dynamic bandwidth allocation which is introduced in this paper has look-up table structure that makes programming possible. This structure is very suitable for implementation and operated in high speed because it require very simple and small chip size.

• Journal of Information Processing Systems
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• v.5 no.3
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• pp.151-158
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• 2009

This paper proposes a utility-based data rate allocation algorithm to provide high-quality mobile video streaming over femtocell networks. We first derive a utility function to calculate the optimal data rates for maximizing the aggregate utilities of all mobile users in the femtocell. The total sum of optimal data rates is limited by the link capacity of the backhaul connections. Furthermore, electromagnetic cross-talk poses a serious problem for the backhaul connections, and its influence passes on to mobile users, as well as causing data rate degradation in the femtocell networks. We also have studied a fixed margin iterative water-filling algorithm to achieve the target data rate of each backhaul connection as a counter-measure to the cross-talk problem. The results of our simulation show that the algorithm is capable of minimizing the transmission power of backhaul connections while guaranteeing a high overall quality of service for all users of the same binder. In particular, it can provide the target data rate required to maximize user satisfaction with the mobile video streaming service over the femtocell networks.

• Journal of Integrative Natural Science
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• v.5 no.3
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• pp.182-185
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• 2012

In this paper, For 4th generation wireless communication systems, we propose a method to predict FH patterns in FH-OFDMA systems. OFDM is recognized as a promising modulation technique. Multi-user allocation in OFDM system can use FH that provides the spectrum-spread techniques. If one can generate more predictable FH sequences, then performance of the system can be easily improved. Current random FH and simple adaptive FH methods, however, are not considering predicting FH sequences. In this paper we show that the sampling of the wireless faded signal is not realized as a certain probability nature. With this regard, the proposed predictive FH allocation method is designed to embed the unknown probability models. Simulation study shows that the predictive FH method is more accurately predict FH sequences than the random or simple adaptive FH methods. We will further improve this proposed method to apply QoS control and MAC function development in OFDMA based wireless physical structures, especially maritime wireless data communications.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.13 no.6
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• pp.2949-2963
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• 2019

A novel distributed compress-and-forward (CF) system based on multi-relay network is presented. In this system, as the direct link between the source and destination is invalid due to some reasons, such as the limited power, special working environment, or even economic factors, relays are employed to receive analog signals and carry on distributed compressed encoding. Subsequently, the digital signals are transmitted to the destination via wireless channel. Moreover, a theoretical analysis for the system is provided by utilizing the Chief Executive Officer (CEO) theory and Shannon channel capacity theory, and the rate-distortion function as well as the connection between the transmission rate and the channel capacity are constructed. In addition, an optimal signal-to-noise ratio (SNR) -based power allocation method is proposed to maximize the quantization SNR under the limited total power. Simulation result shows that the proposed CF system outperforms the amplify-and-forward (AF) system versus the SNR performance.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.32 no.1
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• pp.61-70
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• 2024

In response to the continuously increasing demand for air travel, various studies are being conducted. This research focuses on the design of a simulation model for improving airport slot allocation in the strategic phase. It addresses three aspects of model design, introducing considerations such as the objective function. Additionally, it explains the conceptual procedures for the overall simulation operation and detailed processes within the model including input and output data. Emphasizing the SAL, this study excludes policy and qualitative judgments from its scope. The target airport for application will be confirmed in future research. This study marks a crucial first step toward optimizing air traffic flow, with expectations of contributing to the enhancement of operational efficiency at airports.

• Korean Journal of Computational Design and Engineering
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• v.16 no.6
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• pp.397-406
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• 2011

Since tolerance allocation in a mobile phone camera manufacturing process greatly affects production cost and reliability of optical performance, a systematic design methodology for allocating optimal tolerances is required. In this study, we proposed the tolerance optimization procedure for determining tolerances that minimize production cost while satisfying the reliability constraints on important optical performance indices. We employed Latin hypercube sampling for evaluating the reliabilities of optical performance and a function-based sequential approximate optimization technique that can reduce computational burden and well handle numerical noise in the tolerance optimization process. Using the suggested tolerance optimization approach, the optimal production cost was decreased by 30.3 % compared to the initial cost while satisfying the two constraints on the reliabilities of optical performance.

• Proceedings of the IEEK Conference
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• 1998.10a
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• pp.87-90
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• 1998

Many recent studies have been conducted involving the transport of constant and variable bit rate MPEG-2 video in asynchronous transfer mode (ATM) networks. In this study, the traffic control of supporting MPEG-2 video communications in ATM networks under unloaded or loaded network conditions, in which the generated traffic sources are bursty in nature, are considered. We analyse about MPEG-2 traffic and design a model, which makes use of the ATM OAM funcation in order to support the traffic control functions. To implement the model, we propose a scheme, which combines the performance management OAM function and the bandwidth allocation function. Especially, we design this scheme to control the VBR (Variable Bit Rate)MPEG-2 video traffic.

• Korean Management Science Review
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• v.21 no.3
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• pp.71-84
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• 2004

CRS, which was initially developed to support airline reservation is now the main part of e-business of airlines, and it decides the degree of prompt and accurate itinerary for travelers due to the remarkable difference in availability inquiry and seats reservation information according to CRS joining level CRS joining level also decides the exactness of reservation, ticketing and traffic data collection and plays the most important role in the exactness of advanced forecast of demand, appropriate seats allocation, and overbooking. Therefore, it provides front end function like seats reservation, schedule display, fare inquiry on-line linked with CRS and back office function like sales result of travel agents, accounting administration. stock administration and customer administration and decides the level of an airline's e-business.

• Journal of Korea Multimedia Society
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• v.14 no.9
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• pp.1109-1116
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• 2011

In this paper, we propose a new and fast method for assigning the number of key frames to each shot. At first we segment the entire video sequence into elementary content unit called shots and then the key frame allocation is performed by calculating the accumulated value of AF(activity function). The proposed algorithm is based on the amount of content variation using DC images extracted from compressed video. By assigning the number of key frames to the shot that has the largest value of content function, one key frame is assigned at a time until you run out of given all key frames. The main advantage of our proposed method is that we do not need to use time-exhaustive computations in allocating the key frames over the shot and can perform it fully automatically.