• The Korean Journal of Ecology
• /
• v.15 no.2
• /
• pp.201-208
• /
• 1992

Wild rats inhabiting pundang area where urbanized since 1989 were there species including apodemus agrarius. amoung them, a. agrarius was dominant as shown in other areas of korea. They were captured much more 85.00$\pm$9.46 per ha., 64.40$\pm$7.50 per ha. respectively in may and August than inother seasons all through the year. The proportion of female and male was in the ratio of 2 to 1 regardless of the season and habitat, and this species was inhabiting more at oak forest community in summer and at hill-upland boundary in winter than at other habitats in the same season. The change of environment by new urbanizing did not affect in density of wild rats. In general, seasonal percentage of capture in different habitats inceased in accordance with high density.

• Bulletin of the Korean Chemical Society
• /
• v.27 no.10
• /
• pp.1609-1612
• /
• 2006

The determination of the boron isotopic ratio in solutions was achieved by means of a solid state track detector by using an alpha track. The neutron flux was optimized by using a Cd-foil to find the optimum conditions for counting the number of alpha tracks on the selected solid detector caused by the (n, $\alpha$) nuclear reaction of boron. The home-made multi-dot detector plate was utilized in this study to increase the reproducibility of the measurement by uniformly drying the boron solution within the marked circle area on the detector plate. The experimental results of this study verified that the $^{11}B/^{10}B $ isotopic ratio can be measured by observing the number of alpha tracks for different concentrated standard solutions with various isotopic compositions. This technique was applied to the determination of $^{10}B$ enrichment factor in a biological sample for a boron neutron capture therapy.

• The Journal of Fisheries Business Administration
• /
• v.36 no.1 s.67
• /
• pp.121-138
• /
• 2005

This study was conducted to investigate the economic effect of the release of seed flounder to the central area of the West Sea, which was analyzed into both direct and indirect effects. The results showed that based on the data collected from partial area, the economic effect of flounder seed release reached 6.97 times, average catch proportion was 32.27$\%$, and recapture rate was 11.26$\%$, suggesting that economic effect was very high. In addition, it was observed that the recapture rate was greatly higher than 2.05$\%$, that of Break-Even-Point. It was noted that the increased catch by the release of seed flounder resulted in the increase in commission of sales and the increase in sports fishing. Another economic effect observed were diverse including the increase in income of fishing village, elevated spirit to proper management of fisheries resources, maintaining of willingness to live in fishing village through activation of local fishing village, prevention of illegal fishing including capture of juvenile fish, and the increase in the supply of sea food of high quality. It is emphasized that although the investigation was conducted in the same area, the results will vary by size at release, time at release and other factors. Finally, there is a need to expand species and area of study for more active economic analysis incorporating natural sciences.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.26 no.2
• /
• pp.239-250
• /
• 2022

LoRa is a physical layer technology designed to secure highly reliable long-range communication with introducing loco parentis tree network and chirp spreading spectrum. Since since a leaf can send message to more than one parents simultaneously with a single transmission in a region, packet delivery ratio increases logarithmically as the number of gateways increases. The delivery ratio, however, dramatically collapses even under loco parentis tree topology due to the limitations of ALOHA-like primitive MAC, . The proposed method is intended to exploit SDMA approach to reuse frequency in an area. With the view, TxPower of each sender for each message in a concurrent transmission is elaborately controlled to survive the collision at different gateway. Thus, the gain from the capture effect improves the capacity of resource-hungry Low Power and Wide Area Networks.

• Journal of the Korean Society of Fisheries and Ocean Technology
• /
• v.49 no.4
• /
• pp.432-439
• /
• 2013

This study was performed to assess the current stock condition of elkhorn sculpin along the Uljin area in the East Sea of Korea. To assess the state of the stock, yield-per-recruit (YPR) and spawning biomass-perrecruit (SBPR) analyses were performed. Estimates of $F_{max}$ and $F_{0.1}$ were 2.10/year and 0.48/year, respectively, and those of $F_{35%}$ and $F_{40%}$ were 0.66/year and 0.54/year, respectively. Current fishing mortality was estimated at 0.63/year and the current age at first capture was 2.41years. $F_{40%}$ was set as the target reference point of the stock. SBPR at $F_{40%}$ and current SBPR were estimated to be 41.85g and 37.77g, respectively. Estimated FOTY which is the fishing mortality for the overfished threshold yield was 0.49/year. The ratio of SBPR/$SBPR_{MSY}$ was calculated as 0.90 and that of $F/F_{OTY}$ was 1.05. The ratio of $t_c/t_{c\;opt}$ was calculated as 1.15 and that of $F/F_{OTY}$ was 1.17. Therefore, the current stock condition of elkhorn sculpin along the Uljin area of Korea has not been overfished, however, it indicates that a light overfishing is going on this stock.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2011.11a
• /
• pp.992-995
• /
• 2011

A study on the performance design schemes of the supersonic air intakes applied to the supersonic air-breathing propulsion system(Ramjet/Scramjet) was conducted and for two kinds of air intakes, the preliminary configuration designs and the performance analysis models were established. For axisymmetric conical air intake and two dimensional rectangular air intake, the performance effects were assessed according to compression angles and shock wave numbers.

• Fisheries and Aquatic Sciences
• /
• v.26 no.3
• /
• pp.216-223
• /
• 2023

Pacific yellowtail emperor, Lethrinus atkinsoni Seale, 1910, is one of the most targeted reef fish species in Southern Sulawesi, Indonesia. Therefore, assessing its stock is important to understand the condition of the population, providing valuable inputs for sustainable fisheries management in the area. Here we assess the stock condition of L. atkinsoni in Southern Sulawesi, Indonesia, using the length-based spawning potential ratio model. A total of 4,887 individuals were collected from commercially small-scale fishers from January to October 2022. The total length, sex, and gonad maturity of the individuals were examined. We observed that the fish length ranged from 10.5 to 39.5 cm, with an average length of 23.3 cm. The sex ratio was equal (1:1.2) between male and female individuals. Length at first maturity and length at first capture were 23.4 and 19.6 cm, respectively. In addition, we observed a growth coefficient of 0.45/year, with an asymptotic length of 41.14 cm and natural mortality of 0.6/year. Based on these life history parameters, we observed the spawning potential ratio (SPR) value of 12%, indicating an unsustainable fishery level (SPR of < 30%). Further concerns related to the sustainability of the species and strategy to rebuild stock of the L. atkinsoni in Southern Sulawesi are of utmost importance.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.33 no.7B
• /
• pp.469-476
• /
• 2008

In this paper we analyze the packet interference probability and the aggregated throughput of a WPAN in which a number of Bluetooth piconets share the ISM band with WLANS. Using an Adaptive Frequency Hopping algorithm, when the AFH is employed, the number of hops available to the Bluetooth piconets varies depending on the number of independent WLANs within the piconet's radio range. Using a packet collision model in a piconet cluster, we give an analysis of the packet interference probability and the aggregated throughput as a function of the available hops for the AFH algorithm. We also present an analytical model of packet interference with multi-path fading channel in a cluster of piconets. Through analysis, we obtain the packet collision probability and aggregated throughput assuming capture effect. Numerical examples are given to demonstrate the effect of various Parameters such as capture ratio, Rice factor and cluster size on the system performance.

• KDI Journal of Economic Policy
• /
• v.28 no.2
• /
• pp.179-198
• /
• 2006

This paper estimates relationships between the supply of national highways, measured in lane-km, and the quantity of traffic, measured in vehicle-km traveled. The analysis uses a panel data set of annual observations for the years 1984 to 2003. By using a log-linear lag effect model designed to capture short and long term effects, the paper estimates that national highway vehicle-km traveled has a lane-km elasticity of 0.268 at the country level (Non-Seoul Metropolitan area) and 0.41 at the Seoul metropolitan area for the short term. For the long term, the paper estimates 0.8 for the country level and 1.23 for the Seoul metropolitan area. This paper finds conclusive evidence that increases in highway lane-miles have generated traffic over the period of study, however the increasing ratio of the generated traffic decreases gradually, particularly during the late 1980s.

• The Bulletin of The Korean Astronomical Society
• /
• v.39 no.2
• /
• pp.110.1-110.1
• /
• 2014

The optics of Space telescope is one of the major parts of space mission used for imaging observation of astronomical targets and the Earth. These kinds of space mission have a bulky and complex opto-mechanics with a long optical tube, but there are attempts have been made to observe a target with a small satellite in many ways. In this paper, we describe an optical design of a reflecting telescope for use in a CubeSat mission. For this design, we adopt the off-axis segmented method of astronomical observation techniques based on the Ritchey-Chr$\acute{e}$tien type telescope. The primary mirror shape is a rectangle with dimensions of $8cm{\times}8cm$, and a secondary mirror has dimensions of $2.4cm{\times}4.1cm$. The focal ratio is 3 which can obtain a $0.3{\times}0.2$ degree diagonal angle in a $1280{\times}800$ CMOS color image sensor with a pixel size of $3{\mu}m{\times}3{\mu}m$. This optical design can capture a ${\sim}4km{\times}{\sim}2.3km$ area of the earth's surface at 700 km altitude operation. Based on this conceptual design, we will keep trying to study more for astronomical observation with Attitude control system.