• KSII Transactions on Internet and Information Systems (TIIS)
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• v.8 no.10
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• pp.3342-3360
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• 2014

In this paper, the capacity and BER performance of downlink distributed antenna systems (DAS) with transmit antenna selection and multiple receive antennas are investigated in MIMO composite channel, where path loss, Rayleigh fading and lognormal shadowing are all considered. Based on the performance analysis, using the probability density function (PDF) of the effective SNR and numerical integrations, tightly-approximate closed-form expressions of ergodic capacity and average BER of DAS are derived, respectively. These expressions have more accuracy than the existing expressions, and can match the simulation well. Besides, the outage capacity of DAS is also analyzed, and a tightly-approximate closed-form expression of outage capacity probability is derived. Moreover, a practical iterative algorithm based on Newton's method for finding the outage capacity is proposed. To avoid iterative calculation, another approximate closed-form outage capacity is also derived by utilizing the Gaussian distribution approximation. With these theoretical expressions, the downlink capacity and BER performance of DAS can be effectively evaluated. Simulation results show that the theoretical analysis is valid, and consistent with the corresponding simulation.

• Journal of the Korean Institute of Landscape Architecture
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• v.40 no.6
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• pp.70-78
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• 2012

In order to calculate the ecological carrying capacity of Donggung and Wolji, Gyeongju, the number and time for various activities of tourists were surveyed and then the injury tolerance on lawns was predicted with seven types of various activities. According to the injury tolerance in various activities for the suitable carrying capacity, the normal carrying capacity and the limited carrying capacity were explicitly determined in four lawns. According to the number and time for various activities, the injury tolerance of various activities was predicted in four lawns, and the highest average injury tolerance was 2.15 in walking, the lowest average injury tolerance was 0.05 in lying. The highest injury tolerance was 1.31 in lawn 4, and then the order was 0.97 in lawn 3, 0.91 in lawn1, and 0.70 in lawn 2. The ecological carrying capacity was predicted with a damaged area according to the injury tolerance of various activities. The suitable carrying capacity was done separately to 40 persons, 249 persons, 107 persons, 37 persons, the limited carrying capacity was 116, 713, 306, 107 respectively and the normal carrying capacity was 75, 463, 198, 69 in four lawns. When managed in Donggung and Wolji, Gyeongju, the number of tourists was under the limited carrying capacity, the conformation would grow better.

• Journal of the Korean Society for Heat Treatment
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• v.30 no.6
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• pp.258-263
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• 2017

The effect of cooling rate on the damping capacity of pure Mg was studied. Two Mg samples with different cooling rates were prepared by heat treatment at 873 K for 24 h, followed by water quenching and by furnace cooling to room temperature, respectively. The average grain sizes of the Mg samples were almost identical regardless of the cooling rate, but more twins were observed in the sample with faster cooling rate. The calculated vacancy fraction was higher in the fast cooling sample than the slow cooling one. It is noted that the fast cooling sample exhibited lower damping capacity both in the strain-amplitude independent and strain-amplitude dependent regions. Higher values of vacancy concentration and number density of twins in the fast cooling sample are considered to be responsible for the deteriorated damping capacity in the strain-amplitude independent and strain-amplitude dependent regions, respectively.

• Magazine of the Korean Society of Agricultural Engineers
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• v.10 no.1
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• pp.1413-1419
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• 1968

Yochon reservoir was consturcted with an original storage capacity of 202.7 chung-meters. This reservoir receives the water from watershed area of 933.0 chungbo and has irrigated area of 478.0 chungbo. In 1967 a detailed capacity survey of this reservoir was carried out by a new depth-recorder under the scheme of reservoir sedimentation of Agricultural Engineering Research Center. Significant findings are 1. The capacity of the reservoir for the water storage has been reduced by 8.9%(18.066 chung-meters out of the 202.7 chung-meters) since its construction, a period of just 39.0 years. 2. The sediment accumulation in the reservoir represents an average annual soil loss of 0.496mm depth(0.463 chung-meters) of soil from the watershed area of 933.0 chungbo. Eventually the capacity of the reservoir for the water storage will be reducing by about 25%(50.7 chung-meters out of the 202.7 chung-meters)in one hundred years since its construction. We have to set up controlling projects for those reservoir protections from the sediment, soil loss, and other failures. The depth recorder is very useful, convenient, and accurate machine for surveys of reservoir capacity and other river surveys.

• Journal of the Korean Institute of Navigation
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• v.20 no.3
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• pp.127-135
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• 1996

This study investigated the correlation of physique factor( standing height, body weight, chest girth, body surface ) and vital capacity upon records of swimming discipline at sea water. The subjects are 194 sophomore students of Korea Maritime University who participated in the swimming discipline. The swimming records were divided into three groups - higher, middle and lower group. The results from this investigation are as follow ; 1. The standing height was above the average on the A, B+ record, body weight was above on the A+, A record, and vital capacity was above on the A+, A, B+, C record respectively. 2. The standing height, body weight, chest girth, body surface, vital capacity was significantly correlated between record P < 0.05 and P < 0.01. Therefore the higher record group has better physique factor and vital capacity than the middle or lower record group. 3. The standing higher of the higher record group was significantly correlated with body weight(0.514), body surface(0.768) and vital capacity(0.427), and body weight was significantly correlated with chest girth(0.525), body surface(0.940) and vital capacity. This standing heiht of the middle record group was sigificantly correlated with body weight(0.509) and body surface(0.779), and body weight was significantly orrelated with chest grith(0.618) and body surface(0.927). The standing height of the lower record group was significantly correlated with body weight(0.595), chest grith(0.363), body surface(0.802) and vital capacity(0.250), and body weight was significantly correlated with chest grith(0.678) and body surface(0.952).

• Composites Research
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• v.15 no.3
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• pp.11-17
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• 2002

Cracking of the reinforcements is a significant damage mode in particle or short-fiber reinforced composites because the broken reinforcements lose load carrying capacity. This paper deals with elastic stress distributions and load carrying capacity of intact and cracked ellipsoidal inhomogeneities. Three dimensional finite element analysis has been carried out on intact and broken ellipsoidal inhomogeneities in all infinite body under pure shear. For the intact inhomogeneity, the stress distribution is uniform in the inhomogeneity and non-uniform in the surrounding matrix. On the other hand, for the broken inhomogeneity, the stress in the region near crack surface is considerably released and the stress distribution becomes more complex. The average stress in the inhomogeneity represents its load carrying capacity, and the difference of average stresses between the intact and broken inhomogeneities indicates the loss of load carrying capacity due to cracking damage. The broken inhomogeneity with higher aspect ratio maintains higher load carrying capacity.

• The Korean Journal of Malacology
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• v.32 no.2
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• pp.83-93
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• 2016

For the continuous stable production of oyster, estimation of food availability (F) was carried out in Goseong Bay, south of coast Korea. Primary productivity ranged from 0.07 to $0.44gC/m^2/day$ (average $0.25gC/m^2/day$), lowest in July and highest in January. The distribution of primary productivity at Goseong Bay showed the pattern of "high in the south and low in the north." Food availability (F) was $F{\leq}0$, indicating insufficient food supply, from August to November and F > 0 from January to April. Continuous insufficient food supply was observed at 18 oyster farms in the southern part of the bay and 4 in its northern part. Mortality at the oyster farms was 56% on the average, and around 58% of death occurred during November when food supply was insufficient. The optimal population of cultured oyster per unit flow area was calculated to be $110-115indiv./m^2$ (198-201 indiv./string). When the sea area was divided into 3 regions (A, B, C) according to carrying capacity, the carrying capacity of (A) regions was $52-53indiv./m^2$ (93-95 indiv./string), (B) regions was $142-144indiv./m^2$ (255-259 indiv./string), and (C) regions was $198-202indiv./m^2$ (356-363 indiv./string). In particular, (A) regions showed extremely low productivity. For continuous stable oyster farming at Goseong Bay, it is necessary to control point and non-point source pollution through continuous environmental monitoring and to adjust harvest according to the base carrying capacity during the season of high water temperature.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.49 no.8
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• pp.70-76
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• 2012

In this paper, we propose a power allocation scheme of the unlicensed user based on orthogonal frequency division multiplexing (OFDM) in the TV white space (TVWS). Power constraints in TVWS should be satisfied in the time domain. However, because OFDM has high PAPR (peak-to-average power ratio), it is difficult to satisfy power constraints of TVWS in the time domain. Furthermore, the conventional power allocation schemes cannot be generally applied to unlicensed user in TVWS. Therefore, we propose a power allocation scheme to satisfy power constraints of TVWS by reducing PAPR in the time domain. In addition, we analyze the capacity of the unlicensed user based on OFDM in a closed form. Based on the capacity analysis, as the number of subcarriers decreases, the capacity can be enhanced. In simulation results, we show that the capacity of the unlicensed user increases, as the number of subcarriers decreases and the mean of the channel between the transmitter and the receiver of the unlicensed user increases.

• Korean Journal of Veterinary Service
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• v.44 no.4
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• pp.175-183
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• 2021

This study investigated the status and analyzed of stray dogs, stray cats admitted to the Jeju Animal Shelter during the year of 2015 to 2019, and the infection rates of specific diseases for abandoned dogs. In addition, in 2017 to 2019, the collected intake and outcome data were reviewed to analyze shelter capacity in terms of housing capacity (monthly daily average intake, required holding capacity, and adoption-driven capacity), staff capacity (staff hours required for daily care). Out of 24,557 dogs admitted to the shelter, owners of 1,808 dogs (7.4%) visited the shelter and found their lost dogs, while 3,612 dogs (14.7%) were adopted to new families. However, the number of puppies that were euthanized was the highest at 12,266 (49.9%), and 6,876 (28%) died either death from disease or natural causes because they were detained in shelters. The monthly daily average (MDA), which is one of the indicators for efficient population management of Jeju Animal Shelter, was found to be 17.4 for abandoned dogs and 1.7 for abandoned cats. Seasonal variations were observed for MDA, RHC, MDA adoptions, ADC, and RSDC, indicating that various strategies are needed for shelter management. This study was performed to analyze and interpret meaningful statistics for improving the efficiency of animal shelters in Jeju. However, inconsistent collection of animal statistics limited data compilation. Creation of a basic animal statistics matrix with reference to well-designed matrices from recognized professional animal shelters is essential.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.9
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• pp.4180-4196
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• 2017

In this paper, we analyze average capacity of an amplify-and-forward (AF) cooperative communication system model in multi-relay multiuser networks. In contrast to conventional cooperative networks, relays in the considered network have no embedded energy supply. They need to rely on the energy harvested from the signals broadcasted by the source for their cooperative information transmission. Based on this structure, a two-step selection scheme is proposed considering both channel state information (CSI) and battery status of relays. Assuming each relay has infinite or finite energy storage for accumulating the energy, we use the infinite or finite Markov chain to capture the evolution of relay batteries and certain simplified assumptions to reduce computational complexity of the Markov chain analysis. The approximate closed-form expressions for the average capacity of the proposed scheme are derived. All theoretical results are validated by numerical simulations. The impacts of the system parameters, such as relay or user number, energy harvesting threshold and battery size, on the capacity performance are extensively investigated. Results show that although the performance of our scheme is inferior to the optimal joint selection scheme, it is still a practical scheme because its complexity is much lower than that of the optimal scheme.