• KIPS Transactions on Computer and Communication Systems
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• v.9 no.3
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• pp.45-58
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• 2020

In the current trend of increasing network traffic due to the popularization of cloud service and mobile devices, WAN bandwidth is very low compared to LAN bandwidth. In a WAN environment, a WAN optimizer is needed to overcome performance problems caused by transmission protocol, packet loss, and network bandwidth limitations. In this paper, we analyze the data deduplication algorithm of WANProxy, an open source WAN optimizer, and evaluate its performance in terms of network latency and WAN bandwidth. Also, we evaluate the performance of the two-stage compression method of WANProxy and Zstandard. We propose a new method to improve the performance of WANProxy by revising its data deduplication algorithm and evaluate its performance improvement. We perform experiments using 12 data files of Silesia with a data segment size of 2048 bytes. Experimental results show that the average compression rate by WANProxy is 150.6, and the average network latency reduction rates by WANProxy are 95.2% for a 10 Mbps WAN environment and 60.7% for a 100 Mbps WAN environment, respectively. Compared with WANProxy, the two-stage compression of WANProxy and Zstandard increases the average compression rate by 33%. However, it increases the average network latency by 2.1% for a 10 Mbps WAN environment and 5.27% for a 100 Mbps WAN environment, respectively. Compared with WANProxy, our proposed method increases the average compression rate by 34.8% and reduces the average network latency by 13.8% for a 10 Mbps WAN and 12.9% for a 100 Mbps WAN, respectively. Performance analysis results of WANProxy show that its performance improvement in terms of network latency and WAN bandwidth is excellent in a 10Mbps or less WAN environment while superior in a 100 Mbps WAN environment.

• The KIPS Transactions:PartD
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• v.11D no.6
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• pp.1295-1300
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• 2004

Although model checking has gained its popularity as one of the most effective approaches to the formal verification, it has to deal with the state explosion problem to be widely used in industry. In order to mitigate the problem, this paper proposes an ion technique to obtain a reduced model M' from a given original model M. Our technique Identifies the set of necessary variables for model checking and projects the state space onto them. The model M' is smaller in both size and behavior than the original model M, written M'$\leq$M. Since the result of reachability analysis with M' is preserved in M, we can do reachability analysis with model checking using M' instead of M. The abstraction technique is applied to Push Push games, and two model checkers - Cadence SMV and NuSMV - are used to solve the games. As a result, most of unsolved games with the usual model checking are solved with the ion technique. In addition, ion shows that there is much of time and space improvement. With Cadence SMV, there is 87% time improvement and 79% space one. And there is 83% time improvement and 56% space one with NuSMV.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.5 no.5
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• pp.58-66
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• 2002

We present a planting plan of the buffer-forest belts created at the boundary area of the waste landfill site which is located in the coastal area of Kyubg-Gi province. In order to form a proper section of ground soil excavated from the sea and a forest which shows a distinction of the vegetation stratification, the planting plan with trees, sub-trees, shrubs, and seedlings (produced at a sprout cultivation place) is devised with an adjustment of planting density. 1. The preparation of mounding is required for planting at a waste landfill site. We first estimate an economical and efficient banking height together with the quantity of soil, and prepare a planting ground with excavated ground soil for the consideration of soil recycling. On the planting ground a banking with a height of 1.5-2m is produced by self-supported soil, playing a role in a salt blocking and an irritation layer of planting. Finally, an additional banking with a height of 2m is produced by qualified vegetation soil, forming a vegetation section with a total height of 6m. 2. Since the planning site is located in the border, the planting area is composed of two regions : one is an inclined face (slope 1 : 3) toward the inside of the landfill site and the other is an inclined face (slope 1 : 4) toward the inland. The buffer planting in the former (latter) region consists of wind break forest (mixed-landscape forest) within a width of less than 35m. 3. Based on the data obtained from the literatures and the investigation of local plants, we choose the 21 plant species (such as Pinus thunbergii, Pinus densiflora, Sorbus alnifolia, Albizzia julibrissin and etc.) and the additinal 7 species which are grown at a sprout cultivation palce of the SUDOKWON landfill site (Rosa rugosa, Quercus acutissima, Prunus armeniaca var. ansu., and etc.). Sub-trees with a height of above 2.5m and seedlings are planted with an interval of $1.5{\times}1.5m$ ($0.45roots/m^2$) and $0.5{\times}0.5m$ ($4roots/m^2$), respectively. Here, both trees exhibit communities planting with more than three rows. Shrubs are planted with $9-16roots/m^2$, depending on their size. Since this case study provides a reference of the planting beds as well as a planting plan at the SUDOKWON landfill site, it is not sufficient for the present plan to be utilized for the formation of buffer-forest belts which are used for the analysis of environmental factor and the reduction of environmental pollutants in the sea waste landfill site. Thus, further studies with the ecological basis are demanded for the environment planting restoration in the sea waste landfill site.

• Journal of Dairy Science and Biotechnology
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• v.21 no.2
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• pp.97-104
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• 2003

It is extremely important to destroy the antigenicity of milk proteins for dietetic treatment of infants with milk allergy. Enzymatic digestion of milk protein is not only effective for destroying antigenicity, but it also is less liable to alter the nutritive value. Bovine casein was hydrolyzed with eight different commercial proteases derived from bacterias or fungi, either individually or in combination to eliminate protein allergenicity. The average molecular weight of casein hyrdolysates determined by size exclusion chromatography is about 550${\sim}$2,300 dalton range. Antigenicity of the casein hyrdolysates was not detected by heterologous passive cutaneous anaphylaxis in guinea pig-rabbit antiserum system. The inhibition test on the enzyme-linked immunosorbent assay(ELISA) showed that the antigenicity of casein hydrolysates is lowed up to 1/8,000 than that of intact bovine casein. As the enzyme reaction was carried out by the combination of bacterial and fungal protease, casein hydrolysates showed much lower bitterness and antigenicity. It suggests that these hydrolysates will be applied to many kinds of foods including the development of hypo-allergenic infant formula.

• KIPS Transactions on Software and Data Engineering
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• v.1 no.1
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• pp.55-68
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• 2012

In this paper, we propose a novel method to solve the problem of excessive segmentation out of the method of segmenting regions from an image using Homogeneity Threshold($H_T$). The algorithm of the previous image segmentation based on $H_T$ was carried out region growth by using only the center pixel of selected window. Therefore it was caused resulting in excessive segmented regions. However, before carrying region growth, the proposed method first of all finds out whether the selected window is homogeneity or not. Subsequently, if the selected window is homogeneity it carries out region growth using the total pixels of selected window. But if the selected window is not homogeneity, it carries out region growth using only the center pixel of selected window. So, the method can reduce remarkably the number of excessive segmented regions of image segmentation based on $H_T$. In order to show the validity of the proposed method, we carried out multiple experiments to compare the proposed method with previous method in same environment and conditions. As the results, the proposed method can reduce the number of segmented regions above 40% and doesn't make any difference in the quality of visual image when we compare with previous method. Especially, when we compare the image united with regions of descending order by size of segmented regions in experimentation with the previous method, even though the united image has regions more than 1,000, we can't recognize what the image means. However, in the proposed method, even though image is united by segmented regions less than 10, we can recognize what the image is. For these reason, we expect that the proposed method will be utilized in various fields, such as the extraction of objects, the retrieval of informations from the image, research for anatomy, biology, image visualization, and animation and so on.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.8 no.2
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• pp.430-439
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• 2004

This paper describes a design of 8192/2048-point FFT/IFFT processor (CFFT8k2k), which performs multi-carrier modulation/demodulation in OFDM-based DVB-T receiver. Since a large size FFT requires a large buffer memory, two design techniques are considered to achieve memory-efficient implementation of 8192-point FFT/IFFT. A hybrid structure, which is composed of radix-4 single-path delay feedback (R4SDF) and radix-4 single-path delay commutator (R4SDC), reduces its memory by 20% compared to R4SDC structure. In addition, a memory reduction of about 24% is achieved by a novel two-step convergent block floating-point scaling. As a result, it requires only 57% of memory used in conventional design, reducing chip area and power consumption. The CFFT8k2k core is designed in Verilog-HDL, and has about 102,000 Bates, RAM of 292k bits, and ROM of 39k bits. Using gate-level netlist with SDF which is synthesized using a $0.25-{\um}m$ CMOS library, timing simulation show that it can safely operate with 50-MHz clock at 2.5-V supply, resulting that a 8192-point FFT/IFFT can be computed every 164-${\mu}\textrm{s}$. The functionality of the core is fully verified by FPGA implementation, and the average SQNR of 60-㏈ is achieved.

• Journal of Korean Port Research
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• v.7 no.1
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• pp.43-58
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• 1993

There has been fast progress in economy in Korea derived by a consecutive five-year plan program for economic development started in the early 1960's. In the field of transportation, rapid changes in the technological environment of transportation and communication have brought a revolution of the transport system, of which inter-modal transportation through containerisation is typical. Because of the rapidly growing traffic volumes of cargo, especially container traffic, and lack of investment into transport infrastructure in the past, both road and railway are beyond their capacity. As a result, the public-road network has suffered a serious congestion problem. For instance, in relation to the corridor between Seoul and Pusan, today, it takes about 14 hours for the journey of container trailer through Kyongbu Expressway, for which it used to take only 7 hours in 1986. For the railway, though the congestion problem is not very serious compared with the road sector, a shortage of capacity on certain main lines has emerged as a problem as railway traffic has increased. Furthermore, the further expansion of the system in near future is difficult due to burden of higher construction the cost. Unlike these two modes, coastal shipping, which has been paid relatively less attention for commodity transport in Korea, shows no constraint in this respect. In addition, it is the most cost efficient mode of transport. This work therefore aims to make a proposal for the alternative inland transportation mode, which is to promote the coastal transport of container. Three obstructing factors for the promotion of the coastal transport are investigated and some solutions for those are suggested as follows : First, it appears to be essential to provide exclusive ports for the coastal shipping, that comply with simplification, specialization and rationalization. The optimum size of berths on the exclusive ports in Pusan port is estimated as 16-20. We found that it needs periodical study and publicity on the advantages from the adoption of the coastal mode. Inducing competition in the coastal shipping market is also necessary. For the supply of the fleet in the coastal shipping, chartering of the surplus ships in the oversea shipping is found to be more desirable than new shipbuilding. Second, to solve the fragmentation of the companies which wish to participate in the coastal transport, government has to implement the subsidy policy. The encouragement of participation of the shipping lines engaging in Korea-Japan run and Korea-East South Asia run, into coastal shipping also needs to be considered cautiously. Third, simplification of the document for entry in ports is needed for rational coastal shipping management. We can use B/L (Bill of Lading) for coastal shipping as a prerequisite to get the indemnity by P & I Club. The reduction of the government controls on entering and leaving the ports also needs.

• Journal of KIISE:Databases
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• v.33 no.6
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• pp.620-630
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• 2006

Event-detection is an important application of sensor networks. Join operations can facilitate event-detection with a condition table predefined by a user. When join operations are used for event-detection, it is desirable, if possible, to do in-network join processing to reduce communication costs. In this paper, we propose an energy-efficient in-network join algorithm, called PBA. In PBA, each partition of a condition table is stored along the path from each node to the base station, and then in-network joins are performed on the path. Since each node can identify the parts to store in its storage by its level, PBA reduces the cost of disseminating a condition table considerably Moreover, while the existing method does not work well when the ratio of the size of the condition table to the density of the network is a little bit large, our proposed method PBA does not have such a restriction and works efficiently in most cases. The results of experiments show that PBA is efficient usually and especially provides significant cost reduction over existing one when a condition table is relatively large in comparison with the density of the network, or the routing tree of the network is high.

• The KIPS Transactions:PartB
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• v.13B no.2 s.105
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• pp.105-114
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• 2006

In ubiquitous environment where various kinds of computers are embedded in persons, objects and environment and they are interconnected and can be used in my place as necessary, different types of data need to be exchanged between heterogeneous machines through home network. In the environment, the efficient processing, transmission and monitoring of image data are essential technologies. We need to make research not only on traditional image processing such as spatial and visual resolution, color expression and methods of measuring image quality but also on transmission rate on home network that has a limited bandwidth. The present study proposes a new motion vector estimation algorithm for transmitting, processing and controlling image data, which is the core part of contents in home network situation and, using algorithm, implements a real time monitoring system of multi dimensional images transmitted from multiple cameras. Image data of stereo cameras to be transmitted in different environment in angle, distance, etc. are preprocessed through reduction, magnification, shift or correction, and compressed and sent using the proposed metamorphosis hierarchical motion vector estimation algorithm for the correction of motion. The proposed algorithm adopts advantages and complements disadvantages of existing motion vector estimation algorithms such as whole range search, three stage search and hierarchical search, and estimates efficiently the motion of images with high variation of brightness using an atypical small size macro block. The proposed metamorphosis hierarchical motion vector estimation algorithm and implemented image systems can be utilized in various ways in ubiquitous environment.

• Journal of Korean Society of Steel Construction
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• v.20 no.1
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• pp.105-119
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• 2008

In steel deck bridges suffering directly on wheel load according to the number of serviced years, the occurrence of fatigue cracks increases in structural details, which includes the cross section parts of the longitudinal rib and transversal rib, and so on. Through the control method for these fatigue cracks the increased thickness of the steel deck plate or the application of retrofit detail to the inside of the longitudinal rib was observed to be effective. This study suggests structural details for the retrofitted and non-retrofitted longitudinal rib. The target details in this study are the connection parts of the lo ngitudinal and transversal rib, and the slit parts of transverse rib where fatigue cracks were frequently reported in previous studies. In the analyses, detailed structural analyses were performed as parameters, which include the shape, change of size and attached position. From the results the stress reduction in the target details was observed to be larger in the retroffited details. Also, the improvement of fatigue strength is more effective in the retrofitted details with the vertical rib than the bulkhead plate.