• Title/Summary/Keyword: Development density

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Biofiltration Efficiency of Saccharina japonica for Integrated Multi-Trophic Aquaculture (IMTA) (다영양입체양식을 위한 다시마(Saccharina japonica)의 생물여과효과)

  • Park, Mi-Seon;Min, Byung-Hwa;Kim, Young-Dae;Yoo, Hyun-Il
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.45 no.4
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    • pp.351-357
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    • 2012
  • To determine whether the seaweed Saccharina japonica can effectively utilize dissolved nutrients from Sebastes schlegeli fish cultures, a laboratory experiment was conducted in a static system for 7 days at ESFRI, NFRDI in Korea. The experiment included an S. schlegeli monoculture system and an S. schlegeli-S. japonica IMTA system. Saccharina schlegeli density ($415{\pm}24g$; mean${\pm}$SE) remained the same in all treatments, whereas seaweed density varied across treatments of 0, 0.5, 1, 2, and 3 kg (control and T1-T4, respectively). During the experiment, nutrient ($NH_4^+$ and $PO_4^{3-}$) concentrations were measured at 24-h intervals. $NH_4^+$ concentration of the control group increased from $0.117{\pm}0.021mg/L$ at the start of experiment to $5.836{\pm}0.904mg/L$ at the end of experiment. $NH_4^+$ concentrations of each treatment were $3.004{\pm}0.040$, $2.086{\pm}0.133$, $1.642{\pm}0.121$ and $0.775{\pm}0.007mg/L$ in T1, T2, T3, and T4, respectively, at the end of experiment. The concentration of $PO_4^{3-}$ exhibited a similar trend to $NH_4^+$ concentration. $NH_4^+$ and $PO_4^{3-}$ concentrations significantly decreased with increased S. japonica thallus density each day (P<0.05). The nutrient removal efficiency (NRE) and nutrient uptake rate (NUR) showed different relationships with changes in thallus density; NRE increased but NUR decreased as thallus density increased. Based on measured concentrations of $NH_4^+$ and S. japonica weight, regression analysis defined the relationship between as an exponential function, $Y=3.8165e^{-0.505X}$ ($R^2$ = 0.9552). Our results demonstrated that S. japonica can function as an efficient component in IMTA with environmental and potentially economic benefits for fish hatcheries.

Dietary factors affecting bone mineral density in Korean rural postmenopausal women (농촌지역 폐경후 여성의 골밀도 변화에 영향을 미치는 식이 요인 연구)

  • Choe, Jeong Sook;Ahn, Eun Mi;Kwon, Sung Ok;Park, Young Hee;Lee, Jinyoung
    • Journal of Nutrition and Health
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    • v.45 no.5
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    • pp.470-478
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    • 2012
  • This study was conducted to investigate dietary factors, bone status, and bone loss in postmenopausal women in rural areas. A total of 189 women participated in the follow-up study after two years. Radius, Tibia, and Phalanx SOS (Speed of Sound) was measured on two occasions 2 years apart by ultra-sonic-metry, and % body fat was measured by bioelectrical impedance analysis at the baseline and after 2years. Dietary intake data were collected 4 times at different season by 24-hour recall method, and then calculated as average. Bone density of radius decreased by 4.2% during the two year period. When the subjects were divided into three groups, by bone decline level during two years, the lowest bone loss group had higher potassium and vegetable intake than other groups. Age and calcium intakes showed significant correlation with bone decline rate at tibia. In multiple regressions, the baseline SOS, vitamin A, vegetables and eggs intakes were found to be significant factors for tibia bone decline. In conclusion, dietary factors, such as higher vegetable intake, seem to affect the changes in bone mineral density in more favorable way. Therefore, efforts are needed to enhance the access to nutritional care for rural elderly postmenopausal women.

Nonlinear Approximations Using Modified Mixture Density Networks (변형된 혼합 밀도 네트워크를 이용한 비선형 근사)

  • Cho, Won-Hee;Park, Joo-Young
    • Journal of the Korean Institute of Intelligent Systems
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    • v.14 no.7
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    • pp.847-851
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    • 2004
  • In the original mixture density network(MDN), which was introduced by Bishop and Nabney, the parameters of the conditional probability density function are represented by the output vector of a single multi-layer perceptron. Among the recent modification of the MDNs, there is the so-called modified mixture density network, in which each of the priors, conditional means, and covariances is represented via an independent multi-layer perceptron. In this paper, we consider a further simplification of the modified MDN, in which the conditional means are linear with respect to the input variable together with the development of the MATLAB program for the simplification. In this paper, we first briefly review the original mixture density network, then we also review the modified mixture density network in which independent multi-layer perceptrons play an important role in the learning for the parameters of the conditional probability, and finally present a further modification so that the conditional means are linear in the input. The applicability of the presented method is shown via an illustrative simulation example.

A Study on the Effect of School Site Planning Factors Related to School Location on Increase and Decrease of the Number of Students in Korea (학교 입지 계획요소가 학생수 증감에 미치는 영향에 관한 연구)

  • Yoon, Yong-Gi
    • The Journal of Sustainable Design and Educational Environment Research
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    • v.16 no.1
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    • pp.20-29
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    • 2017
  • In order to prove the hypothesis that the element of school location planning - the density of development, availability of various private institutes, the location of school, the type of school district, the distance to nearby schools, the existence of communal areas, the pedestrian street, the number of road lanes - affects the increase and decrease of the number of students in the long term, we examined the tendency of the number of long-term (24 years). The results of the analysis are as follows: First, the development factors such as development density, location of school, type of school district, distance from neighboring schools, separation of pedestrians and cars are clearly related. Second, the planning factors such as location of private school and installation of pedestrian-only street seem to be related to each other. Third, the number of road lanes and element of "communal area" is irrelevant. This study is limited to generalization of five new metropolitan cities in the metropolitan area, and it is necessary to further elaborate the analysis factors and evaluation criteria.

Development and Predation of a Aphidophagous Gall Midge, Aphidoletes aphidimyza (Roundani) (Diptera: Cecidomyiidae) on Myzus persicae Sulzer (진딧물류를 포식하는 혹파리, Aphidoletes aphidimyza(Roundani)(Diptera: Cecidomyiidae)의 복숭아혹진딧물 포식과 발육)

  • Choe, Man-Yeong;Lee, Geon-Hwi;Baek, Chae-Hun
    • Korean journal of applied entomology
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    • v.40 no.1
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    • pp.45-45
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    • 2001
  • Development and predation of an aphidophagous gall midge, Aphidoletes aphydimyza (Rondani) , on the green peach aphid, Myzus persicae Sulzer, were studied under laboratory and greenhouse conditions. The developmental threshold temperature of the gall midge larvae was estimated to be $13^{\circ}C$. Larval and total developmental periods were 5.3 and 29 days at 25 $\pm$$2^{\circ}C$. The gall midge attacked more aphids as increasing density of peach aphids, and consumed 4 out of 10 peach aphids per day in a petri dish (9 cm in diameter) at maximum. In green house, the gall midge could control the density of the green peach aphids efficiently with a delayed density dependent-like pattern.

The effects of the mulberry and silkworm intake on muscle increase of rats for resistance exercise (오디와 누에 섭취가 rats의 저항성 운동에 따른 근육 증가에 미치는 영향)

  • Yang, Sung Jun;Kim, Chang Yong;Lee, Jo Byoung;Kang, Sung Sun;Lee, Jong Jin
    • Journal of Sericultural and Entomological Science
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    • v.51 no.2
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    • pp.123-129
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    • 2013
  • The purpose of this study is to investigate the effects of supplementation of mulberry powder, mulberry extract and silkworm powder during the 8 weeks of resistance exercise on muscle increase of rats. Fifty males, Sprague-Dawley rat, were randomly divided into 5 groups: CON(control group, n = 10), REG(resistance exercise group, n = 10), MP REG(mulberry powder intake and resistance exercise group, n = 10), ME REG(mulberry extract intake and resistance exercise group, n = 10) and SP REG(silkworm powder intake and resistance exercise group, n = 10). After climbing the ladder without weights during the 1 week of adaptation period, the rats in the resistance exercise group were trained to climb a 0.98-m vertical(80 degree incline) ladder with weights in their tail during 7 weeks(10 times each day, 2 days per week). After exercise, the skeletal muscle was extracted from the flexor hallucis longus. The absolute weight of skeletal muscle was measured by the electronic balance and the relative weight of skeletal muscle about the weight was calculated. The strength and density of legs muscle were analyzed by the computed tomography scan. After 8 weeks of resistance exercise, the absolute weight of skeletal muscle wasn't significant, but it increased in MP REG 8%, ME REG 8% and SP REG 10% compared to REG. The relative weight of skeletal muscle increased significantly in SP REG compared to REG (p < 0.05). Additionally, there was a significant increase of density and strength of the forelegs in SP REG compared to CON (p < 0.05). However, there was no significant increase of density and strength of the hind legs. In conclusion, regular resistance exercise made rats muscle increase and there was more muscle increase effected by providing silkworm.

A Study on Transit-Oriented Development Method to Activate Transit Use for High Urban-Density Muti-Nucleated Seoul (고밀다핵도시 서울의 대중교통이용 활성화를 위한 역 중심 개발 유도방안 연구)

  • Lim, Hee-Ji
    • Journal of Korean Society of Transportation
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    • v.23 no.5 s.83
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    • pp.93-104
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    • 2005
  • Transit-Oriented Development Model, which is recently proposed to activate transit use, is suitable for solving environmental erosion problems of sprawl cities with low urban density. Accordingly this model is inadequate to apply to Muti-Nucleated City with high urban density like Seoul. With this background. this study proposes ways to effectively implement changes from automobile-oriented Seoul to transit-oriented city through comparative analysis of the urban design policy of Station Impact Zone (SIZ) of Seoul and Transit-Oriented Development Policy of Singapore and Tokyo. First, the study suggests that the implementation strategies for Transit-Oriented Development in the job-oriented SIZ and the neighborhood-oriented SIZ should be made separately. In addition, the job-oriented SIZ should be designated as 'Strategic Centers' in Seoul Comprehensive Plan in order to make Transit-Oriented Centers. Lastly, the SIZ should be designated as 'the Empowerment Zones' in order to make the blighted areas around stations viable for redevelopment and new incentive system should be applied to activate setting up transit-transfer facilities.

A Study on Ageing Characteristics and Alloy Elements of SiCp Reinforced Al Matrix Composites (SiCp입자강화 Al 복합재료에 대한 합금원소의 영향과 시효특성에 관한 연구)

  • Kim, Sug-Won;Lee, Ui-Jong;Woo, Kee-Do;Kim, Dong-Keun
    • Journal of Korea Foundry Society
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    • v.21 no.1
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    • pp.7-14
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    • 2001
  • The research on new DRA(discontinuous reinforced alloy) and CRA(continous reinforced alloy) composites has been carried out to improve the properties of ceramic fiber and particle reinforced metal matrix composites(MMCs). Effects of alloying elements and aging conditions on the microstructures and aging behavior of Al-Si-Cu-Mg-(Ni)-SiCp composite have been examined. The specimens used in this study were manufactured by duplex process. The first squeeze casting is the process to make precomposite and the second squeeze casting is the process to make final composite. The hardening behavior was accelerated with decreasing the size of SiCp particle in the composites. It is considered that the dislocation density increased with increasing SiCp size, due to the different thermal deformation between Al matrix and SiCp during quenching after the solution treatment. Peak aging time to obtain the maximum hardness in 3 ${\mu}m$ SiCp reinforced Al composite was reduced than that in large size(5, 10 ${\mu}m$) of SiCp because of difference in dislocation density. Aging hardening responce(${\Delta}H$ = $H_{Max}.-H_{S.T}$) of composites was greater than that of unreinforced Al alloy because of higher density of second phases in matrix.

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