• Journal of the Korea Institute of Military Science and Technology
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• v.27 no.1
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• pp.8-14
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• 2024

In this study, the scale of renewable photovoltaic(PV) panels and hydrogen fuel storage facilities required to achieve "net zero carbon emissions" in military facilities were predicted based on actual electricity consumption. It was set up to expect the appropriate installation size of PV panel and hydrogen fuel storage facility for achieving carbon neutrality, limited to the electricity consumption in the public sector, including national defense and social security administration in Yeongcheon. The experimental results of this paper are largely composed of two parts. First, representative meteorological factors were considered to predict solar power generation in the Yeongcheon area, and solar power generation was estimated through a multiple regression model using deep learning techniques. Second, the size of solar power generation facilities and hydrogen storage facilities in military bases was estimated with the amount of solar power generation and electricity consumption. As a result of this analysis, it was calculated that a site of 155.76×104 m² for PV panels was needed and a facility capable of storing 27,657 kg of hydrogen gas was required. Through these results, it is meaningful to demonstrated the prospect that military units can lead the achievement of "carbon net zero 2050" by using PV panels and hydrogen fuel storage facilities on idle sites of military bases.

• Journal of Korean Society of Water and Wastewater
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• v.12 no.3
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• pp.75-80
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• 1998

Ammonium ion is notorious for the adverse effects upon many of the important uses of water such as toxcity to fish, corrosion of metals and concrete, and concern over man's consumption. A clinoptilolite, which is a naturally occurring zeolite selective for ammonium ion exchange, has been used. Batch isotherm experiments were conducted for measuring ammonium ion exchange capacity. The ion exchange capacity was well described either by the Langmuir equation or by the Freundlich equation. As the particle size of the clinoptilolite decreased, exchange capacity was increased. The smaller particle size enhaced the exchange of ammonium ion due to the greater surface area and decreased diffusion to the exchange sites within the zeolite. Ammonium ion exchange capacity tended to decrease when the temperature increased from $20^{\circ}C$ to $35^{\circ}C$, and the temperature correction factor was found to be 0.98 in the Langmuir equation.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.23 no.6 s.165
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• pp.1055-1064
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• 1999

In this wort ER(electro-rheological) clutch and MR(magneto-rheological) clutch are devised and their performance characteristics such as response time and controllability are compared. As a first step, field-dependent yield stresses of ER and MR fluids are distilled in shear mode. For reasonable comparison between two clutches, a nondimensional design model is established by choosing same design parameters of gap size and number. Following the manufacturing of two clutches, field-dependent torque level, response time to step input, mechanical Power generation to electric power consumption are experimentally measured and compared. In addition, in order to investigate torque controllability of the clutches a sliding mode controller is formulated and experimentally realized. Control bandwidths of two clutches are identified and tracking control responses for desired torque trajectories are presented.

• Journal of the Korean Society for Precision Engineering
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• v.19 no.11
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• pp.129-136
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• 2002

Electric vehicle body has to be subjected to uniform load and demand auxiliary equipment such as air pipe, electric wire pipe and gas pipe. Especially, lightweight vehicle body is salutary to save operating costs and fuel consumption. Cross beam supports the weight of passenger and electrical equipments and account for the most of weight of vehicle body. Therefore this study performs the size and the shape optimization of crossbeam for electric vehicle using GENESIS 7.0 and presents the effect of mass reduction and the shape of hole in cross beam.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.39 no.4
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• pp.357-362
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• 2006

The feeding habits of John Dory (Zeus faber) were studied by examining the stomach contents of 317 specimens collected from January 2004 to December 2005 in the coastal waters off Gori, Korea. The standard length (SL) of the specimens ranged from 12 to 42 cm. Z. faber is a piscivore and consumes mainly teleost fish such as Psenopsis anomala, Trichiurus lepturus and Conger myriaster. Its diet also includes shrimp and cephalopods. Smaller individuals (<25 cm SL) consume shrimp and small fish such as Glossanodon semifasciatus. The proportion of these prey items decreases with increasing fish size, and this decrease is paralleled by increased consumption of lager fish such as Psenopsis anomala and Trichiurus lepturus. The prey size increases with Z. faber size.

• Journal of information and communication convergence engineering
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• v.6 no.3
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• pp.343-347
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• 2008

Wakeup schemes that turn off sensors' radio when communication is not necessary have great potential in energy saving. At the start of each beacon interval in the IEEE 802.11 power saving mode specified for DCF, each node periodically wakes up for duration called the ATIM Window. However, in the power saving mechanism specified in IEEE 802.11, all nodes use the same ATIM window size. Since the ATIM window size critically affects throughput and energy consumption, a fixed ATIM window does not perform well in all situations. This paper proposes an adaptive mechanism to dynamically choose an ATIM window size according to network condition. Simulation results show that the proposed scheme outperforms the IEEE 802.11 power saving mechanism in terms of the amount of power consumed and the packet delivery ratio.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.41 no.1
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• pp.26-31
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• 2008

The feeding habits of chub mackerel (Scomber japonicus) were studied based on an examination of the stomach contents of 512 specimens collected between November 2005 and October 2006 in the South Sea of Korea. The specimens ranged in fork length (FL) from 23.4-37.5 cm. Chub mackerel is a piscivore and consumes mainly Teleosts such as Engraulis japonicus. Its diet also includes amphipods, crabs, Euphausia, chaetognaths and shrimp. Smaller individuals (<26 cm FL) consume mainly crabs. The proportion of these prey items decreases with increasing fish size, and this decrease paralleles the increased consumption of fish. The prey size increases with S. japonicus size.

• Food Science and Biotechnology
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• v.14 no.6
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• pp.758-765
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• 2005

Instant powders that only require mixing with water prior to consumption can be produced by extrusion for use in products such as instant beverages. Both extrusion processing conditions and particle size of powder are important to end-product characteristics. In this study, a twin-screw extruder was used under various processing conditions (feed moisture, barrel temperature, and screw speed) to produce extrudates from soft wheat flour, which were ground to powders with particle size ranges of less than 93, 93-145, and $145-249\;{\mu}m$. Effects of adding soy lecithin to wheat flour before extrusion were also investigated. Water absorption, solubility, suspension viscosity, and dispersibility of wheat powders were related to specific. mechanical energy measured during extrusion. Powder particle size was important to instant properties, especially ease of dispersal in water and stability to sedimentation. Addition of lecithin significantly improved dispersibility of powders.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.47 no.6
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• pp.895-900
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• 2014

The feeding ecology of Doederleinia berycoides from the southern sea of Korea was examined. Specimens were caught monthly from January 2007 to June 2008. The size of the specimens ranged from 6.8 to 39.8cm in total length (TL). The primary prey items of D. berycoides included fishes and shrimps. In autumn, feeding mainly crustacea and fishes feeding mainly in winter. The individuals of smallest size class (less than 15 cm TL) fed mainly on crustacea. The proportion of crustacea decreased as body size increased, whereas the consumption of fishes increased. Fishes accounted for almost (86%) stomach contents of larger individuals (more than 35 cm TL).

• Fisheries and Aquatic Sciences
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• v.7 no.1
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• pp.46-50
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• 2004

Feeding habits of Rudarius ercodes collected from a Zostera marina bed in Jindong Bay, Korea were studied. R. ercodes was a omnivore which consumed mainly gammarid amphipods, polychaetes and eelgrass (z. marina). Its diets also included a small amount of copepods, urochordates and caprellid amphipods. R. ercodes showed ontogenetic changes in feeding habits. Small individuals less than 2cm SL fed mainly on copepods, however, gammarid amphipods and polychaetes were heavily selected with increasing fish size. The consumption of eelgrass by R. ercodes was $10-20\%$ all size classes. The dietary breadth of R. ercodes were varied with fish size