• Parasites, Hosts and Diseases
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• v.58 no.6
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• pp.689-694
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• 2020

Strongyloidiasis is caused by Strongyloides stercoralis and is one of the most neglected tropical diseases in tropical and subtropical regions. Although several strongyloidiasis cases have been reported in Korea, genetic analysis of Korean isolates is still incomplete. In this study, a parasite was isolated from a 61-year-old man diagnosed with strongyloidiasis during the treatment of lymphoma on his retroperitoneal lymph node. Diffuse symmetric wall thickening from the ascending to descending colon and a nematode-infected intestine was observed following microscopic examination. Genomic DNA was isolated from a patient tissue block, and S. stercoralis was identified by PCR and sequencing (18S rDNA). In order to determine phylogenetic location of a Korean isolate (named KS1), we analyzed cox1 gene (500-bp) and compared it with that from 47 previous S. stercoralis isolates (28 human isolates and 19 canid isolates) from Asian countries. Our results showed that phylogenetic tree could clearly be divided into 5 different groups according to hosts and regions. KS1 was most closely related with the Chinese isolates in terms of genetic distance.

• The Journal of the Korea Contents Association
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• v.9 no.7
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• pp.76-85
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• 2009

UWB signal with high resolution capability can be used to estimate ranging and positioning in wireless personal area network. The node works on its local clock and the frequency differences of nodes have serious affects on ranging algorithms estimating locations of mobile nodes. The low rate UWB, IEEE802.15.4a, describes asynchronous two way ranging methods such as TWR and SDS-TWR working without any additional network synchronization, but the algorithms can not eliminate the effect of clock frequency differences. Therefore, the mechanisms to characterize the crystal difference is essential in typical UWB PHY implementations. In high rate UWB, characterizing of crystal offset with tracking loop is not required. But, detection of the clock frequency offset between the local clock and remote clock can be performed if there is little noise induced jitter. In this paper, we complete related ranging equations of high rate UWB based on TWR with relative frequency offset, and analyze a residual error in the ideal equations. We also evaluate the performance of the relative frequency offset algorithm by simulation and analyze the ranging errors according to the number of TWR to compensate coarse clock resolution. The results show that the relative frequency offset compensation and many times of TWR enhance the performance to converge to a limited ranging errors even with coarse clock resolutions.

• Advances in aircraft and spacecraft science
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• v.5 no.4
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• pp.499-513
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• 2018

One of the major problems in glass fiber reinforced epoxy (GFRE) composite pipes is the durability under water absorption. This condition is generally recognized to cause degradations in strength and mechanical properties. Therefore, there is a need for an intelligent system for detecting the absorption rate and computing the mass of water absorption (M%) as a function of absorption time (t). The present work represents a new non-destructive evaluation (NDE) technique for detecting the water absorption rate by evaluating the dielectric properties of glass fiber and epoxy resin composite pipes subjected to internal hydrostatic pressure at room temperature. The variation in the dielectric signatures is employed to design an electrical capacitance sensor (ECS) with high sensitivity to detect such defects. ECS consists of twelve electrodes mounted on the outer surface of the pipe. Radius-electrode ratio is defined as the ratio of inner and outer radius of pipe. A finite element (FE) simulation model is developed to measure the capacitance values and node potential distribution of ECS electrodes on the basis of water absorption rate in the pipe material as a function of absorption time. The arrangements for positioning12-electrode sensor parameters such as capacitance, capacitance change and change rate of capacitance are analyzed by ANSYS and MATLAB to plot the mass of water absorption curve against absorption time (t). An analytical model based on a Fickian diffusion model is conducted to predict the saturation level of water absorption ($M_S$) from the obtained mass of water absorption curve. The FE results are in excellent agreement with the analytical results and experimental results available in the literature, thus, validating the accuracy and reliability of the proposed expert system.

• Journal of Communications and Networks
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• v.18 no.1
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• pp.65-74
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• 2016

Ship ad-hoc network (SANET) extends the coverage of the maritime communication among ships with the reduced cost. To fulfill the growing demands of real-time services, the SANET requires an efficient clock time synchronization algorithm which has not been carefully investigated under the ad-hoc maritime environment. This is mainly because the conventional algorithms only suggest to decrease the beacon collision probability that diminishes the clock drift among the units. However, the SANET is a very large-scale network in terms of geographic scope, e.g., with 100 km coverage. The key factor to affect the synchronization performance is the signal propagation delay, which has not being carefully considered in the existing algorithms. Therefore, it requires a robust multi-hop synchronization algorithm to support the communication among hundreds of the ships under the maritime environment. The proposed algorithm has to face and overcome several challenges, i.e., physical clock, e.g., coordinated universal time (UTC)/global positioning system (GPS) unavailable due to the atrocious weather, network link stability, and large propagation delay in the SANET. In this paper, we propose a logical clock synchronization algorithm with multi-hop function for the SANET, namely multi-hop clock synchronization for SANET (MCSS). It works in an ad-hoc manner in case of no UTC/GPS being available, and the multi-hop function makes sure the link stability of the network. For the proposed MCSS, the synchronization time reference nodes (STRNs) are efficiently selected by considering the propagation delay, and the beacon collision can be decreased by the combination of adaptive timing synchronization procedure (ATSP) with the proposed STRN selection procedure. Based on the simulation results, we finalize the multi-hop frame structure of the SANET by considering the clock synchronization, where the physical layer parameters are contrived to meet the requirements of target applications.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.2
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• pp.1426-1433
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• 2015

CCTV-applied monitoring is an effective measure to suppress potential crimes and record objective relationship; however, there is no methodology that can quantitatively compare and assess the afore-mentioned effects. Thus, this study intended to construct the methodology and analysis application that can measure the changes in the space-corresponding performance of CCTVs depending on installation measures by using 3-dimenstional virtual simulation technology. For analysis, the raster-based Isovist theory was 3-dimensionally expanded and the amount of incident sight line to each point was accumulated. At the same time, the amount of overlapped monitoring in the CCTV cameras that were connected to each measurement node was accumulated for cross-analysis. By applying the examples and analyzing the results, it was possible to construct an analysis application in use of collision detection model and quantify the changes of monitoring performance depending on positioning alternative of the cameras. Moreover, it enabled intuitive review and supplementation by reproducing visible shadow areas in a graph.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.19 no.2
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• pp.203-209
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• 2019

We will be establish the new $q(1{\leq}q{\leq}p-1)$ stores of firm $F_B$ to gain pop/(p+q) over rival firm $F_A$ that has already operate with p stores in a city of population pop. Han proposes inclusion-exclusion algorithm(IEA) that searches maximal pop top 5 location and select the maximum location take account of locate variation with increasing of $q=1,2,{\cdots},p-1$. This paper reduced the orignal graph into partial graph initially and search only q=1 node continually reduced in accordance with increasing $q=1,2,{\cdots},p-1$. If the final result is shown in the case of steel customer between q, the q locations farther separate in order to improve of solution. For the eleven experimental data, this algorithm is a relative simplicity and more optimal solution than Han's IEA.

• Advances in aircraft and spacecraft science
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• v.10 no.6
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• pp.495-519
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• 2023

The drone serves the customers not served by vans. At the same time, considering the safety, policy and terrain as well as the need to replace the battery, the drone needs to be transported by truck to the identified station along with the parcel. From each such station, the drone serves a subset of customers according to a direct assignment pattern, i.e., every time the drone is launched, it serves one demand node and returns to the station to collect another parcel. Similarly, the truck is used to transport the drone and cargo between stations. This is somewhat different from the research of other scholars. In terms of the joint distribution of the drone and road vehicle, most scholars will choose the combination of two transportation tools, while we use three. The drone and vans are responsible for distribution services, and the trucks are responsible for transporting the goods and drone to the station. The goal is to optimize the total delivery cost which includes the transportation costs for the vans and the delivery cost for the drone. A fixed cost is also considered for each drone parking site corresponding to the cost of positioning the drone and using the drone station. A discrete optimization model is presented for the problem in addition to a two-phase heuristic algorithm. The results of a series of computational tests performed to assess the applicability of the model and the efficiency of the heuristic are reported. The results obtained show that nearly 10% of the cost can be saved by combining the traditional delivery mode with the use of a drone and drone stations.

• Journal of the Korean Geographical Society
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• v.50 no.1
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• pp.37-52
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• 2015

The purpose of this study is to elucidate the traits of the spatial orientation of urban residents. The analysis materials are the 110 rough maps which have been collected for the last ten years in Yeonsugu, Incheon metropolitan. The urbanites' spatial orientation are analysed from an aspect of the orientation elements and the orientation frames respectively. As a result, the urban dwellers make use of five elements - path, node, district, landmark, and language clue for their spatial orientation. Again the orientation frames of the urban people are investigated in terms of locating and directing in space. In regard to the former, they tend relatively to depend on horizontal axes based on broad streets and to prefer to position at the center on coordinate system. With reference to the latter, they show to be north-at-the-top directed tendency and to hold higher proportion of exocentric perspective than egocentric. Consequently urban residents tend to form spatial orientation with using five spatial elements, leaning horizontal axis, positioning themselves at the central part of coordinates, directing toward north-at-the-top through exocentric perspective.

• Journal of Korea Spatial Information System Society
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• v.8 no.2 s.17
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• pp.75-89
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• 2006

LBS (Location-Based Service) systems have become a serious subject for research and development since recent rapid advances in wireless communication technologies and position measurement technologies such as global positioning system. The architecture named the GALIS (Gracefully Aging Location Information System) has been suggested which is a cluster-based distributed computing system architecture to overcome performance losses and to efficiently handle a large volume of data, at least millions. The GALIS consists of SLDS and LLDS. The SLDS manages current location information of moving objects and the LLDS manages past location information of moving objects. In this thesis, we implement a monitoring technique for the GALIS prototype, to allow dynamic load balancing among multiple computing nodes by keeping track of the load of each node in real-time during the location data management and spatio-temporal query processing. We also propose a buffering technique which efficiently manages the query results having overlapped query regions to improve query processing performance of the GALIS. The proposed scheme reduces query processing time by eliminating unnecessary query execution on the overlapped regions with the previous queries.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.49 no.4
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• pp.45-54
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• 2012

Location-based services with GPS positioning technology as a key technology, but recognizing the current location through satellite communication is not possible in an indoor location-aware technology, low-power short-range communication is primarily made of the study. Especially, as Chirp Spread Spectrum(CSS) based location-aware approach for low-power physical layer IEEE802.15.4a is selected as a standard, Ranging distance estimation techniques and data transfer speed enhancements have been more developed. It is known that the distance measured by CSS ranging has quite a lot of noise as well as its bias. However, the noise problem can be adjusted by modeling the non-zero mean noise value by a scaling factor which corresponds to the change of magnitude of a measured distance vector. In this paper, we propose a localization system using the CSS signal to measure distance for a mobile node taken a measurement of the exact coordinates. By applying the extended kalman filter and least mean squares method, the localization system is faster, more stable. Finally, we evaluate the reliability and accuracy of the proposed algorithm's performance by the experiment for the realization of localization system.