• Journal of Bio-Environment Control
• /
• v.17 no.4
• /
• pp.252-260
• /
• 2008

This study was conducted to observe the characteristics of mineral nutrient uptake of single-node cutting rose 'Versilla' and to determine optimal nutrient solution control method for soilless culture of 'Versilla' in a closed hydroponic system. Nutrient solution was managed by five different control methods: macro- and micro-element control in aeroponic system (M&M), macroelement control in aeroponic system (M), nutrient solution supplement in aeroponic system (S); electrical conductivity (EC) control in aeroponic system(EC-A); EC control in deep flow technique system(EC-D). The concentration of $NO_3$-N exceeds optimal range whereas P and Mg decreased at the later stage of plant growth with the EC control method, EC-A and EC-D. The overall mineral nutrient content increased with S. On the other hand the nutrient content at the root environment was maintained optimal with M&M and M. The nutrient solution control methods had significantly effect on the cut-flower quality. In the M&M and M, flower length, fresh weight and root activity were higher than those with the other mineral nutrients control methods. The maximal efficiency of photochemistry (Fv/Fm) was higher for M&M, M and S than that with EC-A and EC-D. Based on the above results, it is highly recommended to control nutrient solution by mineral nutrient control methods (M&M and M) in a closed hydroponic system for single-node cutting rose, 'Versillia'.

• Proceedings of the Korea Inteligent Information System Society Conference
• /
• 2003.05a
• /
• pp.377-384
• /
• 2003

B2B EC에서 지능형 에이전트에 대한 요구의 증가와 함께 기업구매자가 직접 전자시장으로부터 구매하는 데스크탑 구매의 요구도 증가하고 있는 추세이다. 본 논문에서는 B2B 상에서 전자시장으로부터의 효율적인 구매를 지원하는 b-Cart 기반 에이전트 시스템의 설계 사례에 대해서 기술한다. b-Cart는 구매자가 소유하고 사용되는 구매자 사이트에 위치한 쇼핑카트로서, 본 논문에서는 B2B EC에서의 b-Cart 기반 에이전트 시스템의 요구 기능을 사용자식별(Identification), 사용자 다이알로그(User Dialog), 상품정보수집(Collection), 물품정보제거(Trashing), 개별 구매의사결정지원(Individual Purchase Decision Support), 조직 구매의사결정지원(Organizational Purchase Decision Support), 협상(Negotiation), 주문처리(Ordering), 지불처리(Payment), 진행사항 추적(Tracking), 구매기록(Recording), 전자구매시스템에 구매기록 전송(Record Transmission), 지식베이스에 새로운 지식 유지(Knowledge Maintenance)으로 정의하고, b-Cart 기반 에이전트 시스템의 메시지 인터페이스를 설계하고 시스템의 구조를 설계하여 프로토타입 시스템인 AgentB의 설계 사례를 소개한다. b-Cart 기반 에이전트시스템은 기업구매자의 전자시장으로부터 구매자 증가함에 따라 분산된 정보를 관리 해주고 통합적으로 구매처리를 해줄수 있는 효과적인 시스템이다. 향 후 B2B EC의 에이전트 시스템은 b-Cart를 기반으로 할 것으로 예측할 수 있다.

• Proceedings of the Korean Society for Agricultural Machinery Conference
• /
• 1997.06c
• /
• pp.89-98
• /
• 1997

This study was conducted to develop an automatic nutrient-solution control system for small-scale growers. The nutrient-solution control system consisted of a low-cost and precise metering device and a personal computer. The system controlled electric conductivity(EC) and pH of nutrient-solution based on the time-based feedback control method with the information about temperature, EC, and pH of the nutrient-soIution. The performance of the nutrient-solution control system was evaluated through the control of EC and pH while compared with those of commercial nutrient-solution control system. Also an experimental cultivation of tomato was conducted to verify and to improve the developed system. Results of this study were as follows. 1. An automatic nutrient-solution control system based on a low-cost and precise metering device was developed. 2. The developed system controlled EC and pH within $\pm$0.05 mS/cm and $\pm$0.2 pH full scale error respectively at $24^{/circ}C$. 3. When using the commercial system, the controlled values of EC and pH of the 500l of water were 1.29 mS/cm and 6.1 pH for the setting points of 1.4 mS/cm and 6.0 pH respectively at $22^{/circ}C$. 4. The developed nutrient-solution control system showed $\pm$0.05 mS/cm of deviation from the setting EC value over the experimental cultivation period. 5. The deviation from the average values of Ca and Mg mass content in the several nutrient-solution were 0.5% and 1.8% respectively.

• Journal of Bio-Environment Control
• /
• v.16 no.3
• /
• pp.199-204
• /
• 2007

This experiment was conducted to investigate the effect of nutrient solution strength on the growth of miniature multiflora P. amabilis and P. Taisuco Red Jewel at two growth stages during four months cultivation in an ebb and flow system. Early stage plants gained the biggest leaf length and width when nutrient solution strength was EC 0.5 or $1.0dS{\cdot}m^{-1}$ in P. amabilis, and EC $1.5dS{\cdot}m^{-1}$ in P. Taisuco Red Jewel. Root length and weight were the greatest when nutrient solution strength was EC $0.5dS{\cdot}m^{-1}$ in both cultivars and this trend was also found in middle stage plants. Fresh and dry weights of leaves increased as nutrient solution strength was elevated and were the greatest when nutrient solution strength was EC $1.5dS{\cdot}m^{-1}$ in P. amabilis. On the contrary elevation of nutrient solution strength decreased fresh weight of roots, being the greatest when nutrient solution strength was EC $0.5dS{\cdot}m^{-1}$. This trend was also found in P. Taisuco Red Jewel and P. amabilis at middle growth stage. The T/R ratio and chlorophyll content increased with nutrient solution strength and were the greatest regardless of cultivar and growth stage when nutrient strength was EC $1.5dS{\cdot}m^{-1}$.

• Elastomers and Composites
• /
• v.33 no.5
• /
• pp.315-323
• /
• 1998

The purpose of this study was to investigate the crosslinking density and reinforcement of rubber compounds with various carbon black loadings, cure systems and cure temperatures. Bound rubber content increased with volume fraction of carbon black in rubber compounds, but total crosslinking density decreased with increasing the bound rubber content. Rate constant of cure reaction was changed significantly by cure system and cure temperature, especially it showed strong dependence on the cure temperature. High activation energys of cure reaction were shown in the rubber compound with high loading of carbon black under EC system and in the rubber compound with low loading of carbon black under CC system. High total crosslinking density of vulcanized compounds appeared in the rubber compound with low loading of carbon black and CC system among cure systems. Typical change of total crosslinking density by EC system was not shown. The highest elastic constant by Mooney-Rivlin equation was shown in the rubber compound with low loading of carbon black and SEC system. Modulus increased as increasing the loading of carbon black in the rubber compounds and showed the order of SEC, CC, and EC system for cure system.

• Journal of Information Technology Services
• /
• v.2 no.1
• /
• pp.75-83
• /
• 2003

Among EC areas. the B2B EC market is being spotlighted as an important interesting research area considering its size and the potential impact on companeies and the whole society. In comparison with private consumers in B2C EC. business buyers in B2B EC have to precisely keep track of the purchase records. and integrate them with the buyer's e-procurement system, which might have been implemented as a part of integrated ERP (Enterprise Resource Planning) systems. There are three approaches for such integration between ERP and e-marketplace in B2B EC; Two previous approaches are Inside-Out approach and Outside-In approach. And a newly, one is b-cart approach. In this paper, we try to survey these three approaches and make a comparison analysis. From this research. we identify that the b-cart approach is the most efficient framework in integrating ERP with e-marketplace in B2B EC.

• Asian-Australasian Journal of Animal Sciences
• /
• v.18 no.9
• /
• pp.1343-1347
• /
• 2005

A total of 108 pigs (including 36 starters, 36 growers, and 36 finishers) were randomly allocated to six treatments, which involved a 2 (Crude Protein (CP): 100 and 80% of control diet)${\times}$3 (Ca, P, Salt (CPS): 100, 80 and 60% of control diet) factorial design to evaluate the effectiveness of reducing CP and CPS in reducing wastewater EC in different stages. Another 72 starters were adopted to examine the effect of the six treatment diets (as mentioned above) on the growth performance of pigs. Activated carbon and Reverse Osmosis System (RO) were adopted to examine the reducing efficiency of wastewater EC, and ion analysis was also applied to compare with the wastewater EC in different stages of the metabolism trial. The results of wastewater EC of the six treatment diets in different stages of metabolism trial demonstrated that diminishing dietary CP or CPS decreased wastewater EC. The largest decrease of EC was approximately 30%, and was achieved with 20 and 40% reduced dietary CP and CPS, respectively. Pig growth performance deteriorated somewhat when dietary CP or CPS was diminished. Wastewater ion concentration was not always consistent with dietary CP or CPS content, except for $NO_2^{-}$, $NH_4^{+}$ and $K^{+}$, which were positively correlated with dietary CP or CPS in different stages. Activated carbon is not effective for reducing wastewater EC, while, RO system is effective (90% elimination rate) in reducing wastewater EC, but the EC of concentrated (excreted) water is around 10% higher than that of intact wastewater, representing an additional problem besides the high cost of RO system treatment.

• Journal of the Korea Society of Computer and Information
• /
• v.7 no.3
• /
• pp.149-157
• /
• 2002

Todays, electronic commerce(EC) results to the revolution and new paradigm of business, more and more Web-based EC applications have emerged. But, it's web systems should be satisfied by customers and it should be successful to buying some goods in virtual stores with easy to use. The usability and acceptance of the EC web system is one of the key factors in the successful construction of EC system. In this paper, we considered the characteristics of information search and decision making process in the design of EC web system to be used easily and to be more acceptable to customers. On the basis of these characteristics, we could classified with the activities of the process of buying in the domestic web systems. And, the log files of experimental tasks were analyzed by the statistical method of data mining. As the these results, the important factors of the process of buying could be summarized, 5 user groups could be seen in EC customers, and the usage patterns of these groups were described. These results could be very useful to design user-oriented EC web system.

• Journal of Digital Contents Society
• /
• v.6 no.1
• /
• pp.79-83
• /
• 2005

Our Digital Carousel enables user to share media objects through media synchronization mechanism. We implemented the Digital Carousel so that the users participated in collaborative work may refer shared media or error objects as the same view to others. This paper explains the design and implementation of the EC_DXS(Error Control in Digital Carousel System). EC_DCS is a system that is suitable for detecting sharing and recovering software error based on multimedia CSCW(Computer Supportes Cooperated Work). With error sharing system, a group cooperating users can share me. applications. From the perspective of multimedia collaborative environment, an error application becomes another interactive presentation error is shared with participant engaged in a cooperative work.

• The Journal of Society for e-Business Studies
• /
• v.4 no.1
• /
• pp.37-58
• /
• 1999

In this paper, we suggest the system analysis method that links IDEF0 and conceptual analysis. Based on the method, we propose the implementation methodology that can be used to build CALS/EC systems in logistics industry. This paper presents data characteristic derived using ICAM DEFinition(IDEF0) and conceptual data modeling. Modeling methodology has been widely used for analysis and design of an enterprise information system. Further IDEF has been considered appropriate for developing functional and database models for the logistics environment.