• 자원리싸이클링
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• 제31권2호
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• pp.40-48
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• 2022

본 연구에서는 바나듐광 염배소-수침출 과정을 거쳐 얻어지는 바나듐 함유 수용액으로부터 바나듐을 암모늄메타바나데이트로 침전시켜 회수할 때, 수용액에 존재하는 다른 성분의 이온들이 바나듐 회수에 미치는 영향을 알아보았다. 바나듐 함유 수용액은 pH가 13 정도인 강알칼리 용액으로서, 암모늄메타바나데이트 침전효율을 높이기 위해서는 수용액 pH를 9 이하로 낮춰야 한다. 그러나 황산으로 수용액 pH를 조절하는 과정에서 알루미늄 이온은 바나듐과 같이 공침되기 때문에 알루미늄 이온을 먼저 제거시켜야 한다. 본 연구에서는 소듐실리케이트를 사용하여 알루미늄-실리케이트 화합물 형태로 침전시킴으로서 알루미늄을 제거하였으며, 이 과정에서 바나듐 손실을 최소화하는 조건에 대하여 알아보았다. 알루미늄 제거 후, 황산을 이용하여 수용액 pH를 9 이하로 조절하는 과정에서 수용액의 실리케이트 성분을 침전시켜 제거하였다. 이 때 황산의 농도와 첨가속도가 바나듐 손실에 큰 영향을 미치며, 가급적 25% 묽은 황산을 사용하여 천천히 첨가함으로서 바나듐 손실을 최소화 하였다. 알루미늄 제거 그리고 수용액 pH 조절 과정을 통하여 얻은 바나듐 수용액에 3 당량의 염화암모늄을 첨가하여 상온에서 침전시킨 결과, 전체적으로 81% 이상의 바나듐을 암모늄메타바나데이트로 회수할 수 있었다. 회수된 암모늄메타바나데이트를 세척한 후 550℃에서 2시간 열처리하여 98.6% 순도의 오산화바나듐을 얻을 수 있었다

• 상하수도학회지
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• 제23권6호
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• pp.871-879
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• 2009

The Korea has high population density, so the precipitation per capita is only one tenth to world average. The water resource in Korea is insufficient. But the leakage in the water distribution system is about 25%, and it is lower than other countries where water utilities are managed well. The pipelines' management also is getting worse because the leakage in the pipelines lower the ground density surrounding pipes. So, managing the leakage in the water distribution system is very important in the view of increasing the water resources and doing the efficient management of the pipeline system. Accordingly this study aimed to conduct a cause-analysis with scientific approaches considering key local factor related to water loss of distribution system and derive better performance indicators which are able to evaluate the real state of water loss management reasonably. Also this research aimed to develop a methodology capable of judging condition of infrastructure of water distribution system.

• Asian-Australasian Journal of Animal Sciences
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• 제18권11호
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• pp.1524-1528
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• 2005

Molecular genetic markers were used to detect chromosomal regions which contain economically important traits such as growth, carcass, and meat quality traits in pigs. A three generation resource population was constructed from a cross between Korean native boars and Landrace sows. A total of 240 F2 animals from intercross of F1 was produced. Phenotypic data on 17 traits, birth weight, body weights at 3, 5, 12, and 30 weeks of age, teat number, carcass weight, backfat thickness, body fat, backbone number, muscle pH, meat color, drip loss, cooking loss, water holding capacity, shear force, and intramuscular fat content were collected for F2 animals. Animals including grandparents (F0), parents (F1), and offspring (F2) were genotyped for 80 microsatellite markers covering from chromosome 1 to 10. Least squares regression interval mapping was used for quantitative trait loci (QTL) identification. Significance thresholds were determined by permutation tests. A total of 10 QTL were detected at 5% chromosome-wide significance levels for growth traits on SSCs 2, 4, 5, 6, and 8.

• International Journal of Industrial Entomology and Biomaterials
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• 제19권2호
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• pp.265-268
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• 2009

Wild silkmoths can be utilised sustainably in the production of silk as an income for resource-poor rural communities. However, attack by parasitoids and predators affect the quality of cocoons and quantity of raw silk produced. A laboratory experiment was undertaken to quantify the effect of parasitoids' (dipteran and hymenopteran) and predators' (ants) exit and ingress holes, respectively, on silk production. The mean number of shells required to produce fifty grams of raw silk was highest with cocoons parasitised by a dipteran and lowest with unattacked cocoons (but with moths already emerged). Degumming loss was highest in parasitised and lowest in unttacked cocoons, but both were not different from cocoons predated by ants. Shell weight was highest in unattacked cocoons, followed by hymenopteran-parasitised and predated cocoons, with the dipteran parasitized ones being the least. Single cocoon weight was greater in hymenopteran-parasitised and predated cocoons than the dipteran-parasitised and unattacked cocoons. Shell ratio or raw silk, floss and yarn weights were higher in unattacked than parasitised and predated cocoons. The total loss in raw silk attributable to attack by parasitoids and predators ranged between 17.4~31.2%. The results offer baseline information for assessment of economic losses in wild silk farming due to parasitoids and predators in the field.

• 한국경영과학회:학술대회논문집
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• 대한산업공학회/한국경영과학회 1996년도 춘계공동학술대회논문집; 공군사관학교, 청주; 26-27 Apr. 1996
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• pp.481-484
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• 1996

When logistics system is integrated with production system and marketing system, it takes a very important role of the business management. In general, measurement of logistics cost in logistics system uses the conventional cost assignment method. However the conventional method may result in the incorrect cost because the overhead cost may be incorrectly assigned to the products. Activity-Based Costing(ABC) was proposed as an alternative method which will distribute the overhead cost to each cost obeject more accurately. ABC assigns cost to activities based on the amounts of resources used by resource driver, and assigns cost to cost objects based on the amount of activities driver. This study proposes two heuristic algorithms. The first algorithm selects the best activity driver for each cost object by using correlation analysis. The best activity driver is the one that minimizes the sum of loss cost and measurement cost of activity driver. The second algorithm selects the best number of activities by using correlation analysis. The pair of activities with the highest correlation are combined into one if the saving of measurement cost is no less than the loss due to inaccurate distribution of overhead cost. In order to demonstrate the procedure and validity of the algorithms, Real data of one year from a paper manufacturer are used.

• 한국전기전자재료학회논문지
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• 제28권3호
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• pp.191-195
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• 2015

Inside the existing superconducting cables, the superconducting wire carries a loss-free current, and the cable former (the stranded copper wire) bypasses the fault current to prevent damage and loss of the superconducting cable when the fault current is applied. The fault-current-limiting-type superconducting cable proposed in this paper usually carries a steady current; but in a fault state, the cable generates self-resistance that makes the fault current lower than a certain width. That is, the superconducting cable that transmitted only a low voltage and a large capacity power repetitively limits the fault current, as does a superconducting current limiter. To complete this structure, it is essential to investigate the mutual resistance relationship between the superconducting wires after applying a fault current. Therefore, in this paper, one kinds of superconducting wires (a wire without a stabilization layer) were connected parallel 4 tapes, respectively; and after applying a fault current, the current, voltage, resistance and thermal stability of the HTS thin-film wires were examined.

• 한국전자파학회논문지
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• 제21권10호
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• pp.1194-1199
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• 2010

본 논문에서는 빔 성형(beamforming) 기술을 사용하는 릴레이 기반 셀룰러 네트웍에서, 순방향 링크 채널 상태에 대한 제한된 피드백 정보를 이용하여, 동시에 전송되는 송신기과 수신기 사이의 직접 링크(direct link)와 중계기(relay station)와 수신기 사이의 중계 링크(relaying link) 간의 간섭을 효과적으로 억제하는 간섭 회피(interference avoidance) 빔 성형 기술을 제안한다. 이를 위해 송신기는 빔 성형을 사용하여 한정된 공간으로만 직접링크 신호 전력을 전송하고, 송신기의 간섭 전력이 도달하지 않는 공간 영역에 위치한 릴레이들의 relaying을 허용함으로써, 효과적으로 직접 링크와 중계 링크간 간섭을 억제할 수 있는 충돌 회피(collision avoidance) 스케줄링 기술을 제안한다. 시뮬레이션을 통해 제안하는 간섭 회피 빔 성형 기술이 중계 링크의 전송 용량을 보장하면서 동시에 전송되는 직접 링크 전송 용량을 최대화 할 수 있음을 보인다.

• International Journal of Control, Automation, and Systems
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• 제6권3호
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• pp.351-363
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• 2008

This paper is concerned with tasking and guidance of networked airborne sensors to achieve fault-tolerant sensing. The sensors are coordinated to locate hostile transmitters by intercepting and processing their signals. Faults occur when some sensor-carrying vehicles engaged in target location missions are lost. Faults effectively change the network architecture and therefore degrade the network performance. The first objective of the paper is to optimally allocate a finite number of sensors to targets to maximize the network life and availability. To that end allocation policies are solved from relevant Markov decision problems. The sensors allocated to a target must continue to adjust their trajectories until the estimate of the target location reaches a prescribed accuracy. The second objective of the paper is to establish a criterion for vehicle guidance for which fault-tolerant sensing is achieved by incorporating the knowledge of vehicle loss probability, and by allowing network reconfiguration in the event of loss of vehicles. Superior sensing performance in terms of location accuracy is demonstrated under the established criterion.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2016년도 춘계학술대회
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• pp.573-574
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• 2016

기존의 Machine Socialization 시스템은 서버를 공유기에 연결하여 사용하였다. 그러나 공유기의 낮은 성능으로 인해 데이터 흐름이 증가할수록 트래픽이 증가하였으며 이에 따라 기기 간 협업 시 데이터의 손실이 높아 작업이 중단되는 문제점이 발생하였다. 이러한 문제를 해결하기 위해 공유기에 연결된 서버를 옮기는 작업이 요구된다. 본 논문에서는 이러한 병목현상을 줄이기 위해 클라우드 서버를 활용하여 기기 간 협업 시 데이터의 손실을 줄일 수 있는 시스템을 제안하였다. 또한 가상화 기술을 통해 기기와 센서를 나누어 관리하여 자원을 효율적으로 활용할 수 있는 시스템을 설계하였다.

• 한국식품저장유통학회지
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• 제5권4호
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• pp.339-341
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• 1998

제주산 감귤의 유통방법에 따른 선도 변화를 조사하고 저온유통의 효과를 검토하였다. 유통 중 성분변화는 상온(17$^{\circ}C$)유통이 저온(5$^{\circ}C$)유통에 비해서 중량감소는 6% 증가, vitamin C는 1.91mg 감소, 당산비는 20% 증가함을 보였다. 상온유통에서 중량감소로 인하여 당산비가 높아져서 (16.11에서 21.75) 감귤의 맛과 선도가 감소된다. 현행 감귤수송은 상온유통을 하고 있으나 고품질 감귤에는 부적합한 것으로 나타나며 고품질 소량생산 지향의 생산 체계에 저온유통체계를 도입하는 것이 상품성 향상에 중요 할 것으로 사료된다.