• KSII Transactions on Internet and Information Systems (TIIS)
• /
• 제10권1호
• /
• pp.200-220
• /
• 2016

Orthogonal frequency division multiplexing (OFDM) signals suffer from the problem of large peak-to-average power ratio (PAPR) which complicates the design of the analog front-end of the system. Companding is a well-known PAPR reduction technique that reduces the PAPR by transforming the signal amplitude using a deterministic function. In this paper, a novel piecewise linear companding transform is proposed. The design criteria for the proposed transform is developed by investigating the relationships between the compander and decompander's profile and parameters with the system's performance metrics. Using analysis and simulations, we relate the companding parameters with the bit error rate (BER), out-of-band interference (OBI), amount of companding noise, computational complexity and average power. Based on a set of criteria developed thereof, we formulate the design of the proposed transform. The main aim is to preserve the signal's attributes as much as possible for a predetermined amount of PAPR reduction. Simulations are carried out to evaluate and compare the proposed scheme with the existing companding transforms to demonstrate the enhancement in PAPR, BER and OBI performances.

• 품질경영학회지
• /
• 제26권1호
• /
• pp.192-200
• /
• 1998

The quickest path problem is one of the important things for quality of services in communication networks. It is to find a path to send a given amount of data from the source to the sink with minimum transmission time, where the transmission time is dependent on both the capacities and the traversal times of the arcs in the network. This is found under the networks that the capacity and the lead time of each ring are predetermined. It is general to solve the quickest path problem using shortest path algorithms. The relevant algorithms proposed till now are based on the capacity of rings in distributed environments. When the configuration of networks is changed, there can be two a, pp.oaches to find the quickest paths. The one is to find new quickest paths, and the other is to update the current quickest paths. As one of the algorithms for the latter, the distributed quickest path update algorithm was proposed. This paper aims to propose the distributed algorithm a, pp.icable to find the quickest path, when the configuration of networks is changed, using the quickest path tree update altorithm, and to verify its possibility of a, pp.ication by analyzing the transmission amount of data from one node to another from the theoretical point of view.

• 한국지능시스템학회논문지
• /
• 제10권2호
• /
• pp.75-82
• /
• 2000

이논문에서는 영상처리 기법과 신경회로망 분류기를 이용하여 냉연강판의 표면에 나타나는 결함을 검출하는 기법을 제안한다. 냉연강판 표면의 입력영상을 웨이블렛 변환하여 영상신호 데이터량을 감소시키고 영상신호의 저주파수 영역에 해당하는 부분영상으로부터 구한 co-occurrence 행렬을 이용하여 주된 특징들을 추출한 후 신경회로망 분류기를 이용하여 표면결함을 분류하는 과정을 밟는다 현장에서 직접입수한 실제 냉연강판 표면결함 영상에 대하여 결함의 검출 및 분류기법을 제시하고 실험을 통해 기존의 백터양자화 기법과 비교하여 우수한 성능을 보임을 입증하였다.

• 한국펄프종이공학회:학술대회논문집
• /
• 한국펄프종이공학회 2007년도 춘계학술대회논문집
• /
• pp.157-165
• /
• 2007

Restoration behavior of folded Korea bank note was studied. The variables were folding radii (0.5, 1, 3, 5. 7, 9 mm) and folding time. Initially, bank note was completely folded to make $180^{\circ}$ against predetermined radius panel, and restored angles were measured according to allowed restoration time. We found as folding radius was smaller and as folding time was longer, restoration speed of folding angle became slower and the amount of final restoration was smaller, respectively. Initial restoration angles were related to the elastic moduli of the bank notes, and final restoration angles were inversely related to the TEA of the bank notes, respectively.

• Management Science and Financial Engineering
• /
• 제3권1호
• /
• pp.1-14
• /
• 1997

We address the problem of determining the sequence of a vehicle with fixed capacity to visit n nodes at which a predetermined amount is picked up and/or delivered. The objective is to minimize the total travel distance of the vehicle, while satisfying the pick-up/delivery requirements and feasibility at all nodes. Existing methods for the problem allows the vehicle to visit a node twice, which is impractical in many real situations. We propose a heuristic algorithm, in which every node is visited exactly once. Computational results using random problems indicate that the proposed heuristic outperforms existing methods for practical range of the number of nodes in reasonable computation time.

• 한국농업기계학회:학술대회논문집
• /
• 한국농업기계학회 1993년도 Proceedings of International Conference for Agricultural Machinery and Process Engineering
• /
• pp.1318-1328
• /
• 1993

Expression of chinese cabbage was conducted in order to investigate its dewatering behavior. Chipped cabbage was packed into cylinder and pressed by piston up to the predetermined pressure on Instron-1000. The rates of dewatering were affected domintantly by the applied pressure, but not significantly by the packed amount of cabbage in the cylinder. The pressure effect was increased very abruptly at first, but the increase rate was very low at high pressure greater than 20 MPa, showing great deviation from linear dependence of flow rate on pressure in Darcy's Law. Therefore, water expression from cabbage was not Newtonian flow of water through cell wall. In fact, the squeezed water contained a lot of solid particles, showing destruction of cell wall. The content of solid particles in expressed water was only slightly lower than the dry matter content of fresh chinese cabbage, determined by drying oven method.

• Journal of Biosystems Engineering
• /
• 제19권1호
• /
• pp.3-8
• /
• 1994

An experiment on the expression and dewatering of chinese cabbage was conducted in order to investigate its dewatering behavior. Chopped cabbage was packed into cylinder and pressed by piston upto the predetermined pressure on Instron-1000. The rates of dewatering were affected domintantly by the applied pressure, but not significantly by the packed amount of cabbage in the cylinder. The pressure effect was increased very abruptly at first, but the increase rate was very low at high pressure greater than 20 MPa, showing great deviation from linear dependence of flow rate on pressure in Darcy's Law. Therefore, water expression from cabbage was not Newtonian flow of water through cell wall. In fact, the squeezed water contained a lot of solid particles, about 3% of solid cabbage particles, showing destruction of cell wall. It appeared that compression and dewatering of vegetable wastes in the low pressure. under 20 MPa, is more desirable for later treatment of the dewater. More researches are needed in order to develop a treatment method for the solid particles in the expressed water before an expeller treatment system can be applied to vegetable wastes.

• 한국멀티미디어학회:학술대회논문집
• /
• 한국멀티미디어학회 2003년도 추계학술발표대회(하)
• /
• pp.1006-1009
• /
• 2003

In a motion estimation method for use in encoding a moving picture, a full-pixel motion vector is estimated by stochastically sampling a pixel to be processed in a predetermined-sized block of a previous frame or a next frame as a reference frame for each of a plurality of equal-sized blocks in a current frame. Then, a half-pixel motion vector is estimated based on the full-pixel motion vector. Accordingly, both the calculation amount and the calculation time required for the motion estimation are effectively reduced. Further, it can be prevented that the hardware becomes complicated. .

• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 1993년도 한국자동제어학술회의논문집(국내학술편); Seoul National University, Seoul; 20-22 Oct. 1993
• /
• pp.692-698
• /
• 1993

This paper presents a Bin-Picking method in which robot recognizes the positions and orientations of jumbled objects placed in a bin, then picks up distinctive objects from the top of the jumble. The jumbled objects are recognized comparing the characteristics extracted from stereo images with those in the CAD data. The 3-D information is obtained using the bipartite-matching method which compares image of one camera with the image of the other camera Then the robot picks up the object which will cause the least amount of disturbance to the jumble, and places it at a predetermined place. This paper contributes to the basic study of Bin-Picking, and can be used in an automatic assembly system without using part sorting or orienting devices.

• 한국건축시공학회:학술대회논문집
• /
• 한국건축시공학회 2011년도 추계 학술논문 발표대회
• /
• pp.135-136
• /
• 2011

A standard of estimation is used as a basis for estimating the predetermined amount of public construction. However, they raise several points of reasonable labor to be presented to a standard of estimation. For this reason, it is difficult to make a reasonable and efficient estimation of the costs, and this situation presents an urgent need for an accurate way of making such a calculation.This study analyzed the productivity of reinforced concrete work by the CYCLONE model, and the estimated optimal labor through sensitivity analysis, and presented the model on the number of optimal labor through sensitivity analysis.