• Journal of The Institute of Information and Telecommunication Facilities Engineering
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• v.7 no.1
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• pp.41-58
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• 2007

A compact and broadband $4{\times}1$ array antenna was developed for 3G smart antenna system testbed. The $4{\times}1$ uniform linear array antenna was designed to operate at 1.885 to 2.2GHz with a total bandwidth of 315MHz. The array elements were based on the novel broadband L-probe fed inverted hybrid E-H (LIEH) shaped microstrip patch, which offers 22% size reduction to the conventional rectangular microstrip patch antenna. For steering the antenna beam, a commercial variable attenuator (KAT1D04SA002), a variable phase shifter (KPH350SC00) with four units each, and the corporate 4-ways Wilkinson power divider which was fabricated in-house were integrated to form the beamforming feed network. The developed antenna has an impedance bandwidth of 17.32% ($VSWR{\leq}1.5$), 21.78% ($VSWR{\leq}2$) with respect to center frequency 2.02GHz and with an achievable gain of 11.9dBi. The design antenna offer a broadband, compact and mobile solution for a 3G smart antenna testbed to fully characterized the IMT-2000 radio specifications and system performances.

• International Journal of Aerospace System Engineering
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• v.4 no.2
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• pp.5-9
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• 2017

In a pressurized fuel supply system of aircraft, a flow passage opening device is required to keep fuel continuously transferred from one tank to the other. The device utilizes balancing weights in order to follow up an acceleration at special conditions such as negative g. It is very difficult to test the device in a real high-speed and high-altitude test since severe test conditions and expensive supports are needed. Therefore, this paper deals with performance analysis of a flow passage opening device through low speed aircraft captive flight tests (CFT) including roll and negative-g maneuvers. It is shown that balancing weights in the device can open the passage in accordance with fuel position.

• Electronics and Telecommunications Trends
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• v.33 no.5
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• pp.24-32
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• 2018

With the advent of new convergence services, the requirements of 5G mobile communication systems are being newly derived. The 5G mobile communication system has been evolving to solve requirements that cannot be satisfied with existing 4G mobile communication systems, such as a high user experience transmission rate, short transmission delay, and high connection density. The evolution of a 5G mobile communication system to meet the new requirements is expected to be dominated by the UDN environment in which a number of small cells are concentrated. The 5G wireless backhaul system, which has advantages in terms of initial installation and operation cost, is expected to be an indispensable choice for connecting many small cells and core networks. This paper therefore looks at the frequency band characteristics and requirements applicable to 5G wireless backhaul systems that can accommodate new situations, and introduces key related technologies that can satisfy the 5G wireless backhaul requirements.. In addition, we describe the research and development trends of a 5G wireless backhaul system that is currently under development.

• KSBB Journal
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• v.4 no.2
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• pp.74-77
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• 1989

To increase the volumetric productivity a contimuous cell-recycled system was implemented. Cell concentrations between 9.2 and 15.0 g/1 were obtatined in the continuous fermentor study. At a 4% xylose feed and a specific oxygen supply rate(SOSR) of 1.04 g O2.hr-g DCW the ethanol yield was 0.36% at dilution rate. This represented a 26-% increase over that of th batch fermentation.

• Fisheries and Aquatic Sciences
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• v.16 no.4
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• pp.261-265
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• 2013

The study was conducted to investigate the responses of the hepatic microsomal cytochrome P450 monooxygenase system in the rock bream Oplegnathus fasciatus after chronic exposure to 0, 1, 2, 4, and $8{\mu}g/L$ tributyltin (TBT) concentrations for 4 weeks. Hepatic cytochrome 450 content and ethoxyresorufin O-deethylation (EROD) activity were found to significantly increase in fish treated with the higher concentration of TBT (${\geq}4{\mu}g/L$); however, no significant changes were observed in penthoxyresorufin O-deethylation (PROD) activity in all treated groups compared to the control group. These findings suggest that exposure to a low TBT concentration (${\geq}4{\mu}g/L$) has the potential to induce cytochrome 450 content and EROD enzyme activity in hepatic tissue in the rock bream.

• The Journal of Korea Robotics Society
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• v.17 no.2
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• pp.118-123
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• 2022

We implemented a real-time cloud robotics application by offloading robot navigation engine over to 5G Mobile Edge Computing (MEC) sever. We also ran a fleet management system (FMS) in the server and controlled the movements of multiple robots at the same time. The mobile robots under the test were connected to the server through 5G SA network. Public 5G network, which is already commercialized, has been temporarily modified to support this validation by the network operator. Robot engines are containerized based on micro-service architecture and have been deployed using Kubernetes - a container orchestration tool. We successfully demonstrated that mobile robots are able to avoid obstacles in real-time when the engines are remotely running in 5G MEC server. Test results are compared with 5G Public Cloud and 4G (LTE) Public Cloud as well.

• Journal of Advanced Navigation Technology
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• v.14 no.2
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• pp.213-219
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• 2010

Recently, a multi-core system is studied for single terminal's operations on various service networks for mobile systems. Therefore, it is expected that mobile systems capable of supporting WCDMA, MC-CDMA, CDMA and WiBro would be developed. Mobile systems for supporting various service networks is able to be implemented on a single chipset via SoC(System one Chip) technology, thus a noble modem design proper for SoC technology is necessary. For high speed data transmission of 4G mobile communication services, OFDM scheme has to be applied. But, an OFDM signal consists of a number of independently modulated subcarriers, and superposition of these subcarriers cause a problem that can give a large PAPR. In this paper, a noble modem design for 4G mobile communication services and PAPR reduction method for solving the PAPR problem are proposed.

• Journal of Food Hygiene and Safety
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• v.13 no.4
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• pp.319-331
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• 1998

The purposes of this study were to develop Hazard Analysis Critical Control Point plan applicable to cook/chilled Pork Bulkogi (broiled sliced pork with sauces) in school foodservice operations and to establish reasonable shelf-life limits by assessing food quality during chilled storage period of 5 days. During the product flow, time-temperature profile was recorded and microbiological analyses including mesophilic and psychrotrophic total plate counts, coliform, and fecal coliform and qualitative analyses of Salmonella and Listeria monocytogenes were done. Chemical analyses (pH, acid value, total volatile basic nitrogen), sensory evaluation, and quantitative analysis of thiamin were conducted for 5 days of chilled storage. The number of mesophiles in raw pork ($4.26{\pm}0.11\;Log\;CFU/g$), seasoning mixture ($5.97{\pm}O.04\;Log\;CFU/g$) and marinated pork ($5.56{\pm}0.21\;Log\;CFU/g$) were below the microbial standards for "requires further cooking" food items. Listeria monocytogenes was detected in seasoning mixture. After heating, the number of mesophiles ($5.17{\pm}0.04\;Log\;CFU/g$) were slightly reduced but it did not meet the microbial guidelines of $5\;Log\;CFU/g$ for "ready-to-eat" foods. No other microbes including pathogens were detected. By reheating the menu item after chilled storage, the number of mesophiles were reduced in every phase of 1st day ($4.62{\pm}0.22\;Log\;CFU/g$), 3rd day ($4.55{\pm}0.20\;Log\;CFU/g$) and 5th day ($4.25{\pm}0.16\;Log\;CFU/g$) of chilled storage, and the number of microbes was below the standard limits for "ready-to-eat" foods. At the fifth day of chilled storage, pH (p<0.05), acid value (p<0.01) and TVBN (p<0.05) showed significant increases. Sensory evaluation results did not show any significant change for 5 days of chilled storage. Thiamin content showed a decrease for 5 days of chilled storage. Consequently, the ideal shelflife recommended for Pork Bulkogi was within 3 days of chilled storage. CCPs for Pork Bulkogi were purchasing and receiving of raw meat and some seasoning ingredients, heating, chilling, chilled storage, reheating, and distribution.

• Journal of applied mathematics & informatics
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• v.25 no.1_2
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• pp.383-388
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• 2007

A (g, f)-factor F of a graph G is Called a Hamiltonian (g, f)-factor if F contains a Hamiltonian cycle. The binding number of G is defined by $bind(G)\;=\;{min}\;\{\;{\frac{{\mid}N_GX{\mid}}{{\mid}X{\mid}}}\;{\mid}\;{\emptyset}\;{\neq}\;X\;{\subset}\;V(G)},\;{N_G(X)\;{\neq}\;V(G)}\;\}$. Let G be a connected graph, and let a and b be integers such that $4\;{\leq}\;a\;<\;b$. Let g, f be positive integer-valued functions defined on V(G) such that $a\;{\leq}\;g(x)\;<\;f(x)\;{\leq}\;b$ for every $x\;{\in}\;V(G)$. In this paper, it is proved that if $bind(G)\;{\geq}\;{\frac{(a+b-5)(n-1)}{(a-2)n-3(a+b-5)},}\;{\nu}(G)\;{\geq}\;{\frac{(a+b-5)^2}{a-2}}$ and for any nonempty independent subset X of V(G), ${\mid}\;N_{G}(X)\;{\mid}\;{\geq}\;{\frac{(b-3)n+(2a+2b-9){\mid}X{\mid}}{a+b-5}}$, then G has a Hamiltonian (g, f)-factor.

• Biomolecules & Therapeutics
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• v.2 no.2
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• pp.173-184
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• 1994

The general and some pharmacological actions of DWP 305 were investigated in animals and the following results were obtained. In central nervous system, DWP 305 had no effects on the pentobarbital induced anaesthesia, locomotor activity, rotarod test, traction test, analgesic action in mice and body temperature in rat. DWP 305 showed no depressive action on convulsion induced by strychnine, electronic shock and pentylenetetrazole. From these results, DWP 305 was considered to have no pharmacological effect on the central nervous system. Furthermore, DWP 305 had no influences on the normal blood pressure and heart rate. In the isolated ileum of guinea pig, DWP 305 inhibited contractive effects against the acetylcholine (10$^{-6}$ g/mι), histamine (10$^{-6}$ g/mι), 5-hydroxytryptamine (10$^{-6}$ g/mι) and BaCl$_2$(10$^{-4}$ g/mι) at a concentration of 2.15$\times$10$^{-4}$ g/ml in bath. In the isolated trachea and vats deference, DWP 305 showed no effect on the contractions produced by histamine and norepinephrine, respectively. DWP 305 showed inhibitory effect on the contractions produced by acetylcholine and oxytocin at a concentration of 2.15$\times$10$^{-4}$ g/ml on the isolated nonpregnant rat uterus. DWP 305 had no effect on the isolated right atrium of guinea pig, bile excretion, urine volume, pH, gastrointestinal motility, gastric secretion and blood aggregation.