• KSII Transactions on Internet and Information Systems (TIIS)
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• 제14권10호
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• pp.4214-4230
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• 2020

This paper introduces a pilot allocation scheme for massive MIMO systems based on deep convolutional neural network (CNN) learning. This work is an extension of a prior work on the basic deep learning framework of the pilot assignment problem, the application of which to a high-user density nature is difficult owing to the factorial increase in both input features and output layers. To solve this problem, by adopting the advantages of CNN in learning image data, we design input features that represent users' locations in all the cells as image data with a two-dimensional fixed-size matrix. Furthermore, using a sorting mechanism for applying proper rule, we construct output layers with a linear space complexity according to the number of users. We also develop a theoretical framework for the network capacity model of the massive MIMO systems and apply it to the training process. Finally, we implement the proposed deep CNN-based pilot assignment scheme using a commercial vanilla CNN, which takes into account shift invariant characteristics. Through extensive simulation, we demonstrate that the proposed work realizes about a 98% theoretical upper-bound performance and an elapsed time of 0.842 ms with low complexity in the case of a high-user-density condition.

• Journal of Communications and Networks
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• 제10권1호
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• pp.79-88
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• 2008

In this paper, we propose efficient peer assignment algorithms for low-latency transmission of scalable coded images in peer-to-peer networks, in which peers may dynamically join and leave the networks. The objective of our algorithm is to minimize the transmission time of a requested image that is scalable coded. When an image is scalable coded in different bit rates, the bit stream encoded in a lower bit rate is a prefix subset of the one encoded in a higher bit rate. Therefore, a peer with the same requested image coded in any bit rate, even when it is different from the requested rate, may work as a supplying peer. As a result, when a scalable coded image is requested, more supplying peers can be found in peer-to-peer networks to help with the transfer. However, the set of supplying peers is not static during transmission, as the peers in this set may leave the network or finish their transmission at different times. The proposed peer assignment algorithms have taken into account the above constraints. In this paper, we first prove the existence of an optimal peer assignment solution for a simple identity permutation function, and then formulate peer assignment with this identity permutation as a mixed-integer programming problem. Next, we discuss how to address the problem of dynamic peer departures during image transmission. Finally, we carry out experiments to evaluate the performance of proposed peer assignment algorithms.

• Management Science and Financial Engineering
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• 제18권1호
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• pp.1-12
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• 2012

In this paper, we report a case study on the common due-date assignment and scheduling problem in a paper remanufacturing system that produces corrugated cardboards using collected waste papers for a given set of orders under the make-to-order (MTO) environment. Since the system produces corrugated cardboards in an integrated process and has sequence-dependent setups, the problem considered here can be regarded as common due-date assignment and sequencing on a single machine with sequence-dependent setup times. The objective is to minimize the sum of the penalties associated with due-date assignment, earliness, and tardiness. In the study, the earliness and tardiness penalties were obtained from inventory holding and backorder costs, respectively. To solve the problem, we adopted two types of algorithms: (a) branch and bound algorithm that gives the optimal solutions; and (b) heuristic algorithms. Computational experiments were done on the data generated from the case and the results show that both types of algorithms work well for the case data. In particular, the branch and bound algorithm gave the optimal solutions quickly. However, it is recommended to use the heuristic algorithms for large-sized instances, especially when the solution time is very critical.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1991년도 한국자동제어학술회의논문집(국제학술편); KOEX, Seoul; 22-24 Oct. 1991
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• pp.1576-1579
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• 1991

This paper discusses on the machine loading and tool allocation (MLTA) problem. Mathematical formulation of the problem is given first. Then a heuristic approach based on Group Technology (GT) is presented to deal with the MLTA problem effectively. By using this approach, part-tool group generation and their assignment to adequate machines can easily be obtained in consideration of the work load on each machine, the number of tool-set replacement, and the total number of cutting tools required through the interactive setting of the desired machine utilization rate.

• 한국경영과학회지
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• 제18권2호
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• pp.1-22
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• 1993

This paper deals with the problem of mixed model assembly line balancing. In mixed model assembly lines, tsks should be assigned to stations in such a manner that all stations have approximately the same amount of work on a production cycle basis. Further in balancing assembly lines, the related tasks, the performing task side and the team tasks should be considered to improve work methods, to give more job satisfaction to workers, and to allow greater flexibility in the design of assembly lines. In this paper, the heuristic dispatch assignment rule is developed to assign evenly tasks of each model to all stations. The heuristic method based on the assignment rule developed is presented for mixed model assembly line balancing with the considerations of the related tasks, the performing task side, and the team tasks. The proposed method is analyzed, and compared with other methods for line balancing.

• 한국시뮬레이션학회:학술대회논문집
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• 한국시뮬레이션학회 2003년도 춘계학술대회논문집
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• pp.155-160
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• 2003

Today, for improvement of container terminal productivity, it is necessary to develop ACT(Automated Container Terminal) But, decision rules for conventional container terminals expose various limitations to be applied to ACT. Specially it is important fact to assignment of containers, because the character of ACT which block layout is vertical for berth. And then there is need which assignment of containers with remarshaling work using ATC(Automated Transfer Crane)s. The objective of this study is to provide the operation rules for remarshaling work in ACT. To analyze the proposed rules, the simulation is performed, and we show efficiency of remarshaling on various remarshaling operation rules.

• 한국경영과학회:학술대회논문집
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• 한국경영과학회 1987년도 추계학술발표회 발표논문초록집; 중소기업협동조합중앙회, 서울; 31 Oct. 1987
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• pp.35-35
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• 1987

Consider a job shop that is modelled as an open queueing network of the Jackson(l957) type. All work stations in the shop have the same number of parallel servers. Two problems are studied : the loading of stations and the assignment of servers, which are represented by loading and assingment vectors, respectively. Ma jorization and arrangement orderings are established to order, respectively, the loading and the assignment vectors. It is shown that reducing the loading vector under ma jorizat ion or increasing the assignment vector under arrangement ordering will reduce the congestion in the shop in terms of reducing the total number of jobs(in the sense of likelihood ratio ordering), the maximum queue length(in the sense of stochastic ordering), and the queue-length vector( in the sense of stochastic majorization). The results can be used to supprot production planning in certain job shops, and to aid the desing of storage capacity. (OPEN QUEUEING NETWORK; WJORIZATION; ARRANGEMENT ORDERINC; LIKELIHOOD RATIO ORDERINC; STOCHASTIC ORDERING)

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2003년도 춘계학술대회 논문집
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• pp.674-677
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• 2003

This work presents a method of point-to-surface assignment for 3D inspection of solder pastes on PCB. A bounding box enclosing the solder paste tightly on all sides is introduced to avoid incorrect point-to-surface assignment. The shape of bounding box for solder paste brick is variable according to geometry of measured points. The surface geometry of the bounding box is obtained by using five peaks selected from the histogram of normalized gradient vectors for measured points. By using the bounding box enclosing the solder paste. the task of point-to-surface assignment is successfully executed. Subsequently, the geometrical features are obtained via surface fitting.

• 대한산업공학회지
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• 제17권2호
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• pp.51-61
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• 1991

This paper presents a heuristic method for the Assembly Line Balancing(ALB) of the large-sized product. In the ALB problem of the large-sized product such as bus and truck, the assignments of the Related Task Groups(RTG), the same side tasks, and team tasks should be considered. In this paper, a new concept of the RTG and two kinds of assignment rules are proposed to resolve the above considerations. The first assignment rule allots the RTG with the constraint of the same side tasks to the station while the second allots the RTG to the station, relaxing the above constraint to increase the applicability of the method. An assignment rule for team tasks is also presented. The benefits of the method are to improve work methods, to give more job satisfaction to workers, and to allow greater flexibility in the design of assembly lines.

• 산업경영시스템학회지
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• 제11권17호
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• pp.39-46
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• 1988

This Paper is concerned with a man-multi machine assignment problem to minimize idle time. Assuming different types of semi-automatic machines with deterministic service-processing time, the problem approaches by sequential dependent one operator can handle several machines, where determine optimal range the cost of idle labor and machine time is to be minimized in preparing a work schedule. The Procedure, to establish man-machine assignment model, and it's results are: (1) Objective function to minimize opportunity loss cost, which is happened by idle time, is verified recursive process through heuristic method. (2) The algorithm, is programmed by BASIC language for personal computer, and a numerical example is given to illustrate the heuristic algorithm. This study will be helpful to enhance productivity of Shopflooras a result of increasing the efficiencies of both operator and machine.