• ETRI Journal
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• v.35 no.1
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• pp.58-68
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• 2013

Five-phase reservation protocol (FPRP) is a contention-based media access control protocol for wireless ad hoc networks. FPRP uses a five-phase reservation process to establish slot assignments based on time division multiple access. It allows a node to reserve only one slot in an information frame. Once a node has reserved a slot, it will cease contending for other slots. As a result, there may be less contending nodes in the remaining slots, so the time slots in an information frame are not fully used by FPRP. To improve time slot utilization, this paper proposes an improved pseudo-Bayesian algorithm, based on which an improved contention access mechanism for FPRP is proposed, in which nodes are allowed to contend for more than one slot in a reservation frame according to a certain probability/priority. Simulation results indicate that the proposed mechanism performs better than FPRP in time slot utilization and hence the network throughput under various scenarios.

• Journal of The Institute of Information and Telecommunication Facilities Engineering
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• v.6 no.3
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• pp.1-7
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• 2007

In this paper, we propose a new prioritized Optical Burst Switching (OBS) protocol based on a hop count, which can provide efficient utilization in optical networks. Under several legacy schemes, a switch drops the burst with the shortest time regardless of its traversed hop count. As a result, a dropped burst that have been traversed many hops might cause increased bandwidth waste compared to one that has traversed a few hops. To improve this problem, we propose the Just Enough Time (JET) with a hop counting scheme which can reduce the wasted bandwidth by prioritizing the burst traversed many hops over others. From the simulation result, it is preyed, we show that the proposed scheme has advantages against legacy schemes in terms of the burst blocking probability and the link utilization.

• 제어로봇시스템학회:학술대회논문집
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• 1991.10b
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• pp.1805-1810
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• 1991

This paper derives the upper and the lower bound of the mean cycle time and the mean service time of the class 6 and the class 4, within which the minimum utilization constrain of the class 4 is guaranteed. Also, derived are conditions under which the token bus network is stable or unstable. These bounds and stable conditions are represented in terms of the high priority token hold time, the token rotation time and the arrival rate and the total station number etc. This paper suggest a parameter tuning algorithm in a partially symmetric token bus network with two classes, which maximizes the token rotation time for a suitable high priority token hold time and at the same time meets the stability condition of the network, the real time constraint and the minimum utilization constraint of the class 4.

• Journal of the Korean Wood Science and Technology
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• v.10 no.3
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• pp.196-196
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• 1982

There is a heavy stocked wood volume in the forest of Kang-Won Province compared with the other forests of Korean Provinces. It mainly, however, consists of non-productive and inferior hardwoods and shrubs which grows naturally. -This naturally grown hardwood forest should be cut and reforested with more economical confierous and diciduous tree species by artificial and natural regeneration under the positive government support. This study was carried out to survey the reasonable and economical utilization measures on harvesting wood products when existing hardwood forest should be cut primarily. This is the rust report on the resources and the classification of tree species by the uses of wood growing in the hardwood forest of Kang-Won Province. According to the investigation, 321 hardwood species are growing in this forest, and 141 species of them are extremely not suitable for wood production. The usable species as fuel wood was 180, and these are able to classify into the 22 groups by the uses of wood.

• Journal of Power Electronics
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• v.16 no.4
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• pp.1367-1374
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• 2016

This paper presents a discrete-time version of voltage and current limited operation using an enhanced direct torque and flux control method for interior permanent magnet synchronous motor (IPMSM) drives. A command voltage vector for airgap torque and stator flux regulation can be uniquely determined by the finite-settling-step direct torque and flux control (FSS-DTFC) algorithm under physical constraints. The proposed command voltage vector trajectories can be developed to achieve the maximum inverter voltage utilization for the discrete-time current limit (DTCL)-based FSS-DTFC. The algorithm can produce adequate results over a number of the potential secondary upsets found in the steady-state current limit (SSCL)-based DTFC. The fast changes in the torque and stator flux linkage improve the dynamic responses significantly over a wide constant-power operating region. The control strategy was evaluated on a 900W IPMSM in both simulations and experiments.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2001.05a
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• pp.32-35
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• 2001

In sheet metal forming process, it is very important to nest blanks optimally to get a maximum utilization ratio(UR) to reduce waste of material. Optimal Blank Nesting algorithm is developed about single nesting, double nesting, fixed slitting width and free slitting width. This algorithm was applied to various practical blanks which are under production. Then new optimal nesting configuration was obtained and higher UR was achieved by this program in each cases.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2000.04a
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• pp.1-4
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• 2000

In general, under the concept of unit load, Automated Storage/Retrieval Systems (AS/RS) have the rack of equal sized cells. However, they are inadequate and inefficient meeting the various sizes of customers' demands in today's business environment. Higher utilization and flexibility of warehouse storage can be achieved by using AS/RS with tile rack of modularized cell. In this paper, the model of AS/RS with the rack of modularized cell is proposed, and the effectiveness of proposed model is presented by way of numerical examples. The model developed in this research, as one type of AS/RS that is more flexible to the size and has higher space utilization than those of existing rack structure, could every useful for the storage of heterogeneous unit load sizes.

• IE interfaces
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• v.24 no.3
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• pp.241-247
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• 2011

This paper develops a mathematical model which searches an optimum lot size of a press line, and applies this model to the scheduling of the press line. This mathematical model is not a widely studied cost model but a model which considers the utilization of the press line under a lean production system. In this paper, the optimum lot size is a minimum lot size which does not exceed the total work time of the press line. A production volume and the priority of the production in the press line are adjusted using this optimum lot size. A mathematical model developed in this paper will allow determining the optimum lot size easily in case of variable production environments such as an introduction of a new product and a fluctuation of production volume of each item. Therefore, our model will make a better scheduling of the press line and will enhance the utilization of it.

• Proceedings of the KIEE Conference
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• 2000.07a
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• pp.552-554
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• 2000

This paper presents algorithm to plan construction and expanding of substation considering contingency accidents by proposing utilization factor according to configuration of bank system. In this paper, at first, proper sphere of supply area in each district which could be standardized with respect to its supply capacity is established under assumption which was made long term load forecasting in district respectively. Secondly, goal of utilization ratio according to configuration of substation bank was set to keep reliability by remaining sound bank when it happen to one bank accidents Finally, optimal construction and expanding of substation considering economy and reliability simultaneously about substation to exceed these ratio could be anticipated.

• Proceedings of the Korea Concrete Institute Conference
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• 2000.10a
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• pp.785-792
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• 2000

Repair and retrofit system of concrete structures has been developed from conventional reinforced concrete overlaying, steel plate bonding and recently to fiber composite systems. Research and study on carbon, aramid, and glass fiber composite system has been actively carried out from all over the world Glass fiber composite is proved to be competitive technically and enconomically, among fiber composite system. CAF system is a system developed locally using all domestic materal, glass fabric and epoxy, and improved in shear bonding property by utilizing silica fume mixed with epoxy. All the tests on material properties, structural behavior, constructiveness at site and quality control procedure proved to be most appropriate system so far developed. Futher research work is and will be under progress for utilization of this system which will be applied to more adverse situation.