• Journal of the Korea Society of Computer and Information
• /
• v.17 no.12
• /
• pp.137-148
• /
• 2012

In this paper, we proposed the location-aware coordinate routing algorithm for improving the performance of routing algorithm by using ZigBee in Smart Grid environment. A distributed address allocation scheme used an existing algorithm that has wasted in address space. The x, y and z coordinate axes from divided address space of 16 bit to solve this problems. However, coordinate routing does not take account of wireless link condition. If wiress link condition is not considered, when the routing table is updated, the nodes with bad link conditions are updated in the routing table and can be chosen as the next hop. This brings out the retransmissions because of received packet's errors. Also, because of these retransmissions, additional power is consumed. In this paper, we propose the location-aware coordinate routing algorithm considering wiress link condition, where reliable data transmission is made and the consumed enegy is minimize. and we compared and connected region and transition region of ZigBee location based routing in the aspect of average number of multi hops, subordinate packet delivery ratio, delay time, and energy consumption of proposed algorithm. It turned out that there were improvements in performances of each items.

• Journal of the Korea Society of Computer and Information
• /
• v.13 no.2
• /
• pp.143-151
• /
• 2008

74% of Internet users use the UCC, and You Tube using firearms in a crime occurred. Internet crime occurred in the online, non-face transaction, anonymous, encapsulation. In this paper, we are studied a Network Forensic Way and a technique analyze an aspect criminal the Internet haying appeared at Internet UCC, and to chase. Study ID, IP back-tracking and position chase through corroborative facts collections of the UCC which used UCC search way study of the police and a public prosecutor and storage way and network forensic related to crimes of Internet UCC. Proof data encrypt, and store, and study through approach control and user authentication so that they are adopted to legal proof data through integrity verification after transmission and storages. This research via the Internet and criminal conspiracy to block the advance promotion, and for the criminal investigative agencies of the Internet will contribute to the advancement forensics research.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.35 no.11C
• /
• pp.889-895
• /
• 2010

MIMO system generally requires more than one antenna at the communication device. However, many wireless devices are limited by size, cost or hardware complexity to one antenna. To overcome such restrictions, we used a new technique, called cooperative communication. We propose a new cooperative transmission strategy system using cross-layer coding method base on H-ARQ for optimal communication. Proposed cooperative H-ARQ system that can improve the above problems and can get the better performance. In proposed cooperative system with H-ARQ method, if the received signal from source node is satisfied by the destination preferentially, the destination transmit ACK message to both relay node and source node, and then recovers the received signal. In addition, if ARQ message indicates NACK message, relay node operates selective retransmission. Based on the simulation results in aspect to BER performance and throughput, the proposed method which combined cooperative system with H-ARQ based on cross-layer coding can improve spectral efficiency reliability of system compared with that of general one by one system.

• Applied Microscopy
• /
• v.29 no.1
• /
• pp.1-10
• /
• 1999

The aim of the present study was to investigate with transmission electron misroscope the comparative morphology of epididymal spermatozoa in two species of the Korean insectivorous bats belonging to 'prolonged sperm storage' type (Rhinolophus ferrumequinum korai) and 'delayed implantation' type (Miniopterus schreibersi fuliginosus). Sperm head of the R. ferrumequinum korai was bullet shaped and that of M. schreibersi fuliginosus was spatula shaped. The nuclei of the sperm head of the R. ferrumequinum korai and M. schreibersi fuliginosus occupied two-third and a half of it, respectively. The segmented columns of R. ferrumequinum korai were about 12 to 14 in number, and those of the M. schreibersi fuligincsus were about 10 to 12. Particularly, a pile of the satellite fibers in middle piece of R. ferrumequinum korai remained the inner aspect of the outer dense fibers, but those of the M. schreibersi fuliginosus were not.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.66 no.12
• /
• pp.1905-1912
• /
• 2017

In recent years, Ulaanbaatar, a capital of Mongolia has witnessed major problem that air quality reaches hazardous level during the winter season. Coal combustion for heating of every house in "Ger" district is main reason. One way to reduce the air pollution is mass usage of electric heater. However, there are several difficulties such as overload and degradation of transformers and other equipment used in distribution and transmission systems as well as power shortage occurrence in evening peak period due to residential consumption. This study aims to contribute for solving the air pollution and power shortage problem in Mongolia. One possible solution could be distributed generation (DG) with photovoltaic (PV) penetration. In this study, PV with energy storage (ES) hybrid system to reduce peak load is analyzed. We proposed the suitable structure of PV-ES hybrid for Mongolian household, and suggested several operation scenarios. Optimal operation algorithm is carried out based on a comparison aspect from economical, grid impact and PV penetration possibility. The economic analyse shows annual income of 520USD, and has a payback period of 8 years for selected scenario. The proposed PV-ES system structure is verified by experimentation set on the building rooftop in city center. The suggested scenario is planned to apply for system in further research.

• Korean Journal of Materials Research
• /
• v.25 no.3
• /
• pp.125-131
• /
• 2015

Fluorine-doped $SnO_2$ (FTO) thin film/Ag nanowire (NW) double layers were fabricated by means of spin coating and ultrasonic spray pyrolysis. To investigate the optimum thickness of the FTO thin films when used as protection layer for Ag NWs, the deposition time of the ultrasonic spray pyrolysis process was varied at 0, 1, 3, 5, or 10 min. The structural, chemical, morphological, electrical, and optical properties of the double layers were examined using X-ray diffraction, X-ray photoelectron spectroscopy, field-emission scanning electron microscopy, transmission electron microscopy, the Hall effect measurement system, and UV-Vis spectrophotometry. Although pure Ag NWs formed isolated droplet-shaped Ag particles at an annealing temperature of $300^{\circ}C$, Ag NWs covered by FTO thin films maintained their high-aspect-ratio morphology. As the deposition time of the FTO thin films increased, the electrical and optical properties of the double layers degraded gradually. Therefore, the double layer fabricated with FTO thin films deposited for 1 min exhibited superb sheet resistance (${\sim}14.9{\Omega}/{\Box}$), high optical transmittance (~88.6 %), the best FOM (${\sim}19.9{\times}10^{-3}{\Omega}^{-1}$), and excellent thermal stability at an annealing temperature of $300^{\circ}C$ owing to the good morphology maintenance of the Ag NWs covered by FTO thin films.

• Fire Science and Engineering
• /
• v.20 no.4 s.64
• /
• pp.72-76
• /
• 2006

Polymer/clay nanocomposites have generated considerable interests in the past decade because adding just tiny amount of clay to the polymer matrix could produce a dramatic enhancement in physical, thermal and mechanical properties. Smectite clays, such as montmorillonite (MMT), are of great industrial value because of their high aspect ratio, plate morphology, intercalative capacity, natural abundance and low cost. In this study, PE/MMT nanocomposites were directly prepared by melt intercalating PE and the modified clay. The nanostructure was verified by X-ray diffraction (XRD) and transmission electron microscopy (TEM), and their flame retardant properties were measured and discussed by limiting oxygen index (LOI), char yield and smoke mass concentration. And their thermal stabilities were measured by differential thermogravimetric (DTG) and thermogravimetric analysis (TGA). The PE/MMT nanocomposites proved more effective the conventional composites in reinforcement. Two functions in the thermal stability of the PE/MMT nanocomposite, one is the barrier effect to improve the thermal stability, and another is catalysis, leading to a decrease of the thermal stability. The flammability was greatly decreased due to the formation of the clay-enriched protective char during the combustion.

• Journal of KIISE:Information Networking
• /
• v.29 no.2
• /
• pp.188-196
• /
• 2002

As networked virtual environment (NVE) scales in terms of users and network latency, a key aspect to consider is scalability for interactive performance because a large number of objects likely impose heavy burden especially on the network and computational resources. To improve the scalability, various relevance-filtering mechanism have been proposed. However, the existing filtering mechanism do not scale well in terms of interactive performance as the number of users increase and crowds in a specific place. In this paper, we propose a new scalable filtering scheme which reduces the number of messages by dynamically grouping users based on their interests and distance. Within a group, members communicate with each other with high fidelity. However, a representative sends up-to-dated group information of members with low transmission frequency when they are not of immediate interest but are still within the interest area. The representative is elected from members of the group in distributed manner. The proposed scheme enhances the interactive performance scalability of large-scale NVE systems as much as 18% compared with the existing approach.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.12 no.12
• /
• pp.2307-2314
• /
• 2008

The study that automates the variety of equipment using the USN(Ubiquitous Sensor Networks) has been executed, and the research field is ranged to almost all fields including a road, harbors. building, military affairs, agriculture and home. By deploying these sensors into the greenhouse environment, we can monitor the environmental change and the growth of plants 24 hours a day. However, the limited resources of a sensor node like limited energy, short transmission range etc, make it difficult to expand the size of the sensor networks. In this paper, we studied to expand the site of sensor networks by using WMN(Wireless Mesh Networks) with simulation. With this simulation, we could validate that using the Wireless Mesh Networks technology for expanding sensor networks is more efficient in the energy aspect than the normal sensor network.

• Journal of Veterinary Science
• /
• v.21 no.4
• /
• pp.56.1-56.13
• /
• 2020

Background: The live bird market (LBM) plays an important role in the dynamic evolution of the avian influenza H5N1 virus. Objectives: The main objective of this study was to monitor the genetic diversity of the H5N1 viruses in LBMs in Indonesia. Methods: Therefore, the disease surveillance was conducted in the area of Banten, West Java, Central Java, East Java, and Jakarta Province, Indonesia from 2014 to 2019. Subsequently, the genetic characterization of the H5N1 viruses was performed by sequencing all 8 segments of the viral genome. Results: As a result, the H5N1 viruses were detected in most of LBMs in both bird' cloacal and environmental samples, in which about 35% of all samples were positive for influenza A and, subsequently, about 52% of these samples were positive for H5 subtyping. Based on the genetic analyses of 14 viruses isolated from LBMs, genetic diversities of the H5N1 viruses were identified including clades 2.1.3 and 2.3.2 as typical predominant groups as well as reassortant viruses between these 2 clades. Conclusions: As a consequence, zoonotic transmission to humans in the market could be occurred from the exposure of infected birds and/or contaminated environments. Moreover, new virus variants could emerge from the LBM environment. Therefore, improving pandemic preparedness raised great concerns related to the zoonotic aspect of new influenza variants because of its high adaptivity and efficiency for human infection.