• The Journal of The Korea Institute of Intelligent Transport Systems
• /
• v.7 no.2
• /
• pp.70-80
• /
• 2008

CSMA(Carrier Sense Multiple Access) is a media access control protocol when nodes use a shared channel. To reduce the probability of collision and increase the performance, the station lust checks the state of the channel. In this paper, we study the performance improvement method based on p-persistent strategy. The p-persistent method reduces the chance of collision and improves the efficiency. However, a probability p and the number of station affect the performance. This paper proposes a dynamic CSMA multiple access based on the network status. If the possibility of collision is low, the station increases the probability p to improve the performance. In the opposite case, the station decreases the probability p. Our simulation results show that the proposed scheme outperforms any methods of CSMA multiple access according to the current persistent strategy.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.35 no.9
• /
• pp.933-938
• /
• 2011

In this study, the heat transfer characteristics and NOx and CO emissions of a heat exchanger were investigated using a premixed burner. The experiments involved changing the distance between the burner and heat exchanger to 30, 40, and 50 mm with various equivalence ratios. The results showed that the NOx and CO emissions increased as the equivalence ratio was increased because the flame temperature increased, regardless of the distance between the burner and heat exchanger. In particular, the CO emission increased significantly as the distance between the burner and heat exchanger was decreased. The optimal equivalence ratio for the A-type heat exchanger (distance between the burner and heat exchanger: 30 cm) was 0.7 in the experimental range. In this case, the CO and NOx emissions were 94.5 ppm and 11.2 ppm, respectively, and the efficiency was 84.1%.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2008.10a
• /
• pp.320-323
• /
• 2008

Due to the improvement of mobile device capabilities, a demand for various contents service is increasing. But the differences from heterogeneous mobile devices force to develop contents which is dependent on a mobile. To solve this problem, adaptation course that reorganize contents by the device capability is needed. In this course, device description is described using device description language but there are some problems that is absence of device description repository and the way to get device description data. In this paper, I suggest device description acquisition module and define the interfaces to access device description repository that I designed and implemented.

• The Korean Journal of Mycology
• /
• v.36 no.2
• /
• pp.178-182
• /
• 2008

Although the number of patients with Acanthamoeba keratitis has increased dramatically since the widespread use of contact lens, it is still very hard to cure the disease. The proteases from the Acanthamoeba were reported to play important role in the pathogenesis of keratitis. In this study, the inhibitors for extracellular serine proteases of A. castellanii were screened from the extracts of 230 mushroom samples collected from various regions of Korea. The mushrooms were extracted with methanol and water ($65^{\circ}C$). Filtered and concentrated extracts (0.3 mg/ml) were preincubated with proteases before addition of peptide substrate N-succinyl-ala-ala-pro-phe p-anilide. The selected extracts showing strong inhibitory effects were characterized. Although inhibition with single extract was not so high enough, the complete inhibition was achieved with combination of two extracts. The selected extract showed little effect on other serine proteases such as thrombin (human and bovine) and on general protease such as protease K.

• Journal of the Mineralogical Society of Korea
• /
• v.25 no.4
• /
• pp.263-270
• /
• 2012

Two kinds of uranium species, oxidized uranium(VI) and reduced uranium(IV), were prepared to be interacted with goethite and montmorillonite to identify sorption characteristic of uranium species, which are very sensitive to the redox-reaction. The reduced uranium was prepared by diluting a substantial uranium(IV) that was concomitantly produced during a sulfate reduction via a sulfate-reducing bacterium. The sorption amount of uranium(IV) by the minerals was relatively lower than that of uranium(VI) because the aqueous uranium(IV) had fine colloidal forms to cause its weak adsorption onto the mineral surfaces. We found that the uranium(IV) phase has a nano-colloid character by the transmission electron microscope, suggesting that the uranium species possibly migrating with the flow of groundwater in underground environments can be the colloidal uranium(IV) as well as the ionic uranium(VI).

• The KIPS Transactions:PartD
• /
• v.12D no.4 s.100
• /
• pp.531-542
• /
• 2005

In this paper, we propose the MDBMS(Multi-DataBase Management System) which integrates the LDBMSs(Local DataBase Systems) with heterogeneous environment into distributed system and provides global users with rapidly query process. For designing the MDBMS, we define the functions of components and design the interaction among them. In a point of view of the global view manager in components, we describe the following 3 cases; (1)the case which the results for the global query are all stored to the global view repository, (2)the case which no result exists in the global view repository, and (3)the case which the partial results we stored to the global view repository. By comparing above cases, we establish the functionalities of our MDBMS through the sequence diagram including the interlace of among objects and the method calling. Finally, we propose the model designed in the concrete by showing the executing procedures of each function using sample query on established functions mentioned above.

• Korean Journal of Veterinary Service
• /
• v.41 no.1
• /
• pp.41-45
• /
• 2018

An 11 year-old male Korean short-haired cat was presented to local animal hospital due to weight loss, vomiting, and intestinal hypomotility. After the cat was euthanized by poor clinical outcomes, necropsy was performed at Animal and Plant Quarantine Agency. At necropsy, the stomach was enlarged and had some nearly complete pellet food and the yellow mucous contents. The lumen of the middle and lower parts of the jejunum became narrow. Histopathologically, medium-sized lymphoid cells with hyperchromatic nuclei enclosed by scant cytoplasm were diffusely proliferated from mucosa to serosa of the small intestine. These findings were mainly observed in the jejunum and slightly in the duodenum and ileum. The monomorphous lymphocytes were 1 to 1.5 times larger than red blood cells and had few mitotic figures. Metastasis of the tumor cells to other organs was not observed. In the result of immunohistochemical analysis for identifying the origin of tumor cells, CD3 was expressed, but $CD79{\alpha}$ was not detected in the infiltrated cells. This case was diagnosed as T cell intestinal lymphoma in a Korean short-haired cat based on the clinical signs, gross findings, histopathology, and immunohistochemistry.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
• /
• v.29 no.6
• /
• pp.631-639
• /
• 2011

There are problems in using existing fisheries maps, because of deterioration of paper maps, as well as various coordinate systems. In this study, accuracy of fishery maps in World Geodetic System are evaluated. Materials on fishery rights in the Jeollanam-do Province, a study area, used many kind of coordinate systems. During digitization, these coordinate systems have been converted and unified in one World Geodetic System, and one projection origin. In this research, the accuracy of the products of digitization is verified using DGPS surveying. The RMSEs are minimum of 4.62m(at the Younggwang Seas) to maximum of 17.47m(at the Jangheung Seas), and average of 11.97m. The results shows that the digitized fishery maps meet the accuracy standard of 1/25,000 digital topographic maps.

• Journal of the Korean Society of Tobacco Science
• /
• v.15 no.1
• /
• pp.34-48
• /
• 1993

This experiment were conducted to investigate heterosis and combining ability for several mutant characters by analyzing dialled crosses of flue-cured tobacco. In a dialled cross of 3 flue-cured varieties and the mutant line 83H -5, the heterosis was somewhat higher in Fl than in F2. For growth character, the heterosis was 0.28-6.03% in plant height, leaf number, leaf shape index and yield, and was 43.2% for bacterial wilt disease index. The mutant line 83H-5 showed significantly negative GCA effect for plant height, leaf width and bacterial wilt disease index in Fl and F2, leaf length in F2, and positive GCA effect for total alkaloids, total nitrogen in Fl and days to flower in F2, respectively. Specific combining ability(SCA) in 83H-5 x Hicks was significant in negative effect for leaf length(F2), number of leaves(F2), leaf shape(F1, F2), bacterial wilt(F2) and alkaloids(F1), and in 83H-5 x NC 2326 in positive effect for leaf length(F1, F2) and leaf width(F2), and for 83H-5 x NC 82 in positive effect for plant height(F1, F2) and leaf width(F2), and for 83H-5 x NC 82 in Positive effect for Plant height(F1, F2), leaf length(F2) and yield(F1, F2).

• Korean Journal of Medicinal Crop Science
• /
• v.11 no.2
• /
• pp.127-134
• /
• 2003

One hundred sixty species among Korean medicinal plants were tested on their antioxidative potentials. Antioxidants are useful materials which could be expected into development as food preservatives, health foods, cosmetics and drugs. Korean peninsula have many potential in antioxidant source which includes various medicinal herbs. It grounded on the fact that Korean medicinal plants have been used as folk therapy for long time and still do in oriental medicine. From the study, effective free radical scavengers compared with ${\alpha}-tocopherol\;of\;13.5{\mu}g/ml\;in\;RC_{50}$ were Geranium sibiricum, Geum japonicum, Geranium nepalense subsp. thunbergii and Paulownia coreana which showed $19.3{\mu}g/ml,\;22.5{\mu}g/ml,\;23.9{\mu}g/ml,\;and\;27.2{\mu}g/ml$, respectively, Acer mono and 38 plants showed strong potential in inhibition rate on linoleic acid oxidation (above 90%). In conclusion, we expect that the selected medicinal plants must be more studied as antioxidant and then developed as many industrial materials.