• Title/Summary/Keyword: following system

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The Effects of Temperature on Maintaining the Stability of Water Quality in Biofloc-based Zero-water Exchange Culture Tanks (Biofloc을 기반으로 한 무 환수 사육 시스템의 수질 안정 유지에 미치는 수온의 영향)

  • Cho, Seo-Hyun;Jeong, Jong-Heon;Kim, Myung-Hee;Lee, Kyu-Tae;Kim, Dae-Jung;Kim, Kwang-Hyun;Oh, Sang-Pil;Han, Chang-Hee
    • Journal of Life Science
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    • v.25 no.5
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    • pp.496-506
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    • 2015
  • This study explored adequate water temperature ranges for maintaining stable water quality in a biofloc- based zero-water exchange culture system. Five experimental tanks with the following temperatures were set up: 10℃, 15℃, 20℃, 25℃, and 30℃. First, a biofloc-based culture system was developed in the experimental tanks; then, the tanks were stocked with goldfish and went without a water exchange for 60 days. Conditions for developing a biofloc-based culture system and stable water quality in low concentrations of inorganic nitrogen compounds at 10℃, 15℃, 20℃, 25℃, and 30℃ were maintained after 17, 26, 43, 68, and 78 days, respectively. Beginning from when the goldfish were stocked in the biofloc-based culture tanks, concentrations of $NH_4{^+}-N$ remained constant and at low levels at 10℃ and 15℃, but they showed a gradual increase at 20℃, 25℃, and 30℃. Concentrations of $NO_2{^-}-N$ and $NO_3{^-}-N$ at 10℃ and 15℃ did not remain at low levels and immediately increased. While $NO_2{^-}-N$ concentrations at above 20℃ remained constant and stable at relatively low levels, $NO_3{^-}-N$ concentrations showed a gradual increase. Conditions of 15℃ and below could not maintain low and stable concentrations of $NO_2{^-}-N$. In the pH range of 4.0 to 6.0, $NH_4{^+}-N$ concentration decreased as the pH rose. However, there was no correlation between pH and $NH_4{^+}-N$ concentration in the pH range of 6.0 to 8.0. These results indicate that pH levels should be kept at pH 6.0 and above to maintain a low and stable concentration of $NH_4{^+}-N$ at above 20℃.

EFFECT OF VARIOUS MECHANICAL TREATMENTS OF HYDROXYAPATITE-COATED IMPLANT SURFACES (Hydroxyapatite 피막 처리된 임프란트에 대한 여러가지 기계적 표면처리방법이 임프란트 표면조도 및 성상에 미치는 영향)

  • Yang, Kyung-Ran;Jung, Oh-Chul;Lee, Jae-Mok;Suh, Jo-Young
    • Journal of Periodontal and Implant Science
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    • v.24 no.1
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    • pp.131-143
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    • 1994
  • For maintenance of exposed implant in healthy state, it is necessary to treat the surface of implant fixture and provide the surface adjustable to surrounding tissues. Variable techniques have been introduced such as citric acid and air-abrasive system to treat the failed implant. Although when the rough surface of HA coated implant was exposed to oral environment, the surface treatment method with citric acid or air-abrasive system is effective for removal of bacterial endotoxin, it is unsuccessful to prevent plaque deposition due to difficulty in removal of rough surface of HA coated implant. Thus, in this study the method that removes bacterial endotoxin and makes smooch surface without alteration of surface characteristics was studied. HA coated disc manufactured by IMZ Co. Was treated with high speed diamond bur, low speed diamond bur, stone bur, rubber point, jetpolisher. And then its surface state was examined with profilometer and SEM to evaluate the surface smoothness, and its surface component was analyzed with EDX to evaluate wheter the surface characteristics were altered or not. As a result, following results were obtained. When the surface roughness of each implant disc was measured by profilometer, the group I showed a $R_{max}\;2.11{\mu}m$ and the group II, III, IV, V showed a $R_{max2}\;4.17{\mu}m$, $7.28{\mu}m$, $8.61{\mu}m$ and $39.44{\mu}m$ respectively. That is, surface smoothness was highest in the group I and it has been gradually decreased in the group II, III, IV and V. Under the SEM examination, the group I showed relatively smooth surface and the group II showed slightly rougher surface than the group I due to partially remaining HA particles while most HA particle was removed. The group III and IV showed rough topography due to HA particles that was not grinded, and HA coated surface in group V showed very irregular surface with deep groove and prominence. In cross-sectional view, the group I showed uniform surface, and the group III, IV showed rough surface due to remaining HA particles but the thickness of HA coating was remarkably reduced. The group II has similar pattern in group I, and the group V showed about $40{\mu}m$ thickness although it was not constant. By analysis of surface component with EDX, the group II in which the grinding was effective showed a small quantity of calcium and phosphorous and the group III, IV, in which the grinding was incomplete showed calcium and phosphorus peak. In all experimental group, no other than titanium, aluminum, calcium, phosphorus was observed.

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Population density of potato virus vectors In the Kwanghwal Area, Kimje-gun, Cholla-Pukto, on the western coast (씨감자 생산을 위한 매개 진딧물 조사 - 전북 김제군 광활면의 진딧물 분포상 -)

  • Paik Woon Hah
    • Korean journal of applied entomology
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    • v.7
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    • pp.5-13
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    • 1969
  • Present system of seed potato production in Korea has several weak points and consequently has difficulties in covering annual shortage of 60,000 tons of seed potatoes. The author has an opinion that this so called 'High land system' of seed potato production adopted by the Government should be replaced by the 'Coastal area system' which is proposed by the author and has many advantages over present 'High land system'(2). In coastal areas where enormous acreage of rice paddies are spread, mostly around the villages. the primary host plants of the vectors are found. Therefore, the only source of aphid vectors are limited to the villages. The farmer's houses scattered more sparsely also have minor importance. In the previous paper(2), the author reported that the aphid vector populations were lower in the coastalareas than at Taegwanryong where the Alpine Experiment Station for the production. of seed potatoes is located. However, the number to vectors at Okku showed rather high density, where the trap was placed at the distance of 200 m from a village where peach and Hibiscus trees, the primary hosts of Myzus pesrsicae and Aphis gossypii were grown. To clarify the flight distance from the source of the aphid vectors, a trial was carried out in the Kwanghwal area, Kimje-gun, Cholla-pukto. on the western coast. 13 traps were placed at four directions and the distances between the traps were 250 m. (Fig. I) The traps 'Were operated from June 21 to October 31. The results are shown in Table 1. A total of some 70 species of aphids were found, including 5 speceis of potato virus vectors. The vectors are as follows: I. Myzus persicae (Sulzer) 2. Aphis gossypii Glover 3. Aulacorthum solani (Kaltenbach) 4. Lipaphis erysimi (Kaltenbach) 5. Macrosiphoniella sanborni (Gillette) Out of a total of 12,797 aphids, 5,187$(48\%)$ vectors were found. The trap catches at the 13 locations are shown in Fig. 2 and the numbers of the vectors at each location for each vector, except Macro-siphoniella sanborni. of which only a single individual was caught, are shown in Fig. 3-6. Number of vectors at C (3,279) (Centre of the village) is considerably higher than that at Suwon (763); however, EI. SI. WI and NI. where the distanecs from Care 250 m, showed lower numbers of vectors than that at Taegwanryong (347). The number of vectors at NI was rather than at the other 3 locations at the distance of 250m from the village. This was because C was in the southern part of the village. Consequently NI was much closer to the village than the other 3 locations of the same distance from C. Numbers of catches of the most important vector. Myzus persicae, are shown in Fig.3. The distribution pattern is typical except $S-2\;and\;W_3$, where several farmer's houses were found. If only the rice paddies were found in these locations. the numbers of the vectors would be small as the distances increase. Numbers of catches of the other 3 vectors are shown in Fig. 4-6. From these results. the author has drawn the following conclusions: 1. The aphid vector sources at the rice paddy belt in the western coast are the villages. 2. The vector densities at the locations where the distances are 250 m from the centre of the village are lower than that at Taegwanryong. 3. The vector densities become gradually lower as the distances from the centre of village increase. However. depending on the host plant situation at each location, the vector densities are variable. These minor sources of aphid vectors may be eliminated so that seed potatoes can be grown. 4. Thus. under the direction of specialists, fields suitable for seed potato production can be found in the coastal areas.

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Estimating the Carrying Capacity of a Coastal Bay for Oyster Culture -II. The Carrying Capacity of Geoie-Hansan Bay- (굴 양식수역의 환경용량 산정 -II. 거제 · 한산만의 환경용량-)

  • Park Jong Soo;Kim Hyung Chul;Choi Woo Jeung;Lee Won Chan;Kim Dong Myung;Koo Jun Ho;Park Chung Kil
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.35 no.4
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    • pp.408-416
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    • 2002
  • A 3D hydrodynamic-ecological coupled model was applied to estimate carrying capacity in Geoje-Hansan Bay where is one of the most important oyster culturing grounds in Korea. We considered the carrying capacity as the difference between food supply to the oysters and food demand, considering monthly difference of the actual growth. The food supply to the system was determined from the results of the model simulation (tidal exchange and chlorophyll $\alpha$) over the culturing period from September to May of the following year. The food demand was estimated from the food concentration (chlorophyll $\alpha$) multiple the filtration rate of oysters that is considered monthly different growth rate of oysters and food concentration. The values of carrying capacity for the system varied from 6.1 ton/ha (minimum carrying capacity) in february to 14.91 ton/ha (maximum carrying capacity) in April of marketable size oysters (>4 g wet-tissue weight) depending on temporal variations in the food supply. The oyster production calculated from present facilities was 9 ton/ha in wet-tissue weight in Geoje-Hansan Bay. This value corresponded to $60\%$ of maximum carrying capacity of the system. The optimal carrying capacity without negatively affecting on oyster production was 5.5 ton/ha when calculated from annual statistic data and 6.1 ton/ha when determined by this study. These results suggest that it must be reduced $32\%$~$39\%$ of oyster facilities in the system.

COMPARATIVE STUDY ON THE EARLY DETECTION OF ENAMEL LESIONS USING DIFOTI AND LASER FLUORESCENCE (Digital Imaging Fiber-Optic Trans-Illumination과 Laser Fluorescence를 이용한 법랑질 우식증의 조기 진단에 관한 비교 연구)

  • Maeng, Myoung-Ho;Kim, Seung-Oh;Kim, Jong-Soo
    • Journal of the korean academy of Pediatric Dentistry
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    • v.33 no.2
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    • pp.207-220
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    • 2006
  • The newly developed equipments for the early detection of carious lesion are LFD (laser fluorescence device), Ultrasonic diagnostic system, CLSM(confocal laser scanning microscopy), QLF(quantitative light-induced fluorescence) and DIFOTI (digital imaging fiber-optic trans-illumination) system. In this study, DIFOTI system and LFD were used for the detection of early enamel caries. Twenty five primary teeth extracted from twenty one children at around the dentitional exchanging period were selected as samples. The results obtained from DIFOTI imaging and LFD measurement were compared with those of CLSM and comprehensive evaluations were made for the diagnostic capacity of each device. In vitro test, 40 sample teeth with their buccal & lingual surface formed by a window of $2{\times}3mm$ in diameter were immersed in artificial demineralizing solution for the period of 4, 8, 12 and 16 days. The results obtained from the experimental groups (DIFOTI, LFD) were compared to control group (CLSM) and we have reached to the following conclusions. 1. The sensitivity and specificity of DIFOTI system operated in oral environment was 88.2% and 76.9% respectively. 2. The sensitivity and specificity of LFD measured in oral environment was 76.5% and 69.2% respectively. 3, Regression analysis on the light transparent rate of DIFOTI showed its decrease according to the length of primary enamel decalcification performed in vitro(r=-0.96, p<0.05). 4. No statistically significant difference between LFT measurement and the length of in vitro decalcification was found in regression analysis (p>0.05). 5. The correlation coefficient of DIFOTI image transparent rate and the lesion depth of CLMS was -0.6988 (p<0.05), whereas no statistically significant difference was found for LFD measurement.

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Legal Relations of the Contract of International Carriage of Goods by Air (국제항공화물운송계약(國際航空貨物運送契約)의 법률관계(法律關係) -화주(貨主)의 권리의무(權利義務)를 중심(中心)으로-)

  • Lee, Kang-Bin
    • The Korean Journal of Air & Space Law and Policy
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    • v.1
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    • pp.193-222
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    • 1989
  • The purpose of this study is to review the rights and duties of cargo owners, the party to the contract of international carriage of goods by air under the Warsaw Convention System and the IATA conditions. It is generally known that air freight is the most-cost mode of transportation. However, should there be considerations of total distribution cost, the use of air freight leads exporters to be advantageous in physical distribution. The Warsaw Convention System defined and limited the rights and duties of cargo owners and air carriers paticipating in the international carriage of goods, but it does not regulate every aspect of air transportation. Therefore, the unregulated parts are governed by national laws and by individual contracts of carriage. The International Air Transport Association(lATA), a worldwide organization of airlines, has formulated model conditions of contract for the carriage of cargo. These models are not uniformly followed but they serve as a basis for many of the individual standard form of contracts prepared by air carriers. The contract of air carriage of goods is a contract of adhesion, 'the consignor recognizing and accepting the conditions laid down by the carrier'. There are consignors and carriers as the parties to the contract of international carriage of goods. In addition to his basic right, implied in Warsaw Convention Article 18 and 19, to require devery of the goods in good condition and at the date agreed upon, the consignor has the right to dispose the goods in the course of the journey up to the moment when the consignee is entitled to require delivery. If it is impossible to carry out the orders of the consignor, the carrier must so inform him forthwith. The right conferred on the consignor ceases at the moment when that of the consignee begins in accordance with Warsaw Convention Article 13. Nevertheless, if the consignee declines to accept the air waybill or the goods, or if he cannot be communicated with, the consignor resumes his right of disposition. Unless it is otherwise agreed, it is the duty of the carrier to give notice to the consignee as soon as the goods arrive. The consignee is entitled, on arrival of the goods at the place of destination, to require the carrier to hand over to him the air waybill and to deliver the goods to him, on payment of the charges due and on complying with the conditions of carriage set out in the air waybill. The air waybill is supposed to be made out by the consignor. If the carrier makes it out, he is deemed, subject to proof to the contrary, to have done so on behalf of the consignor, whether there is one air waybill or several, each must be made out in three original parts. The first is for the carrier, the second is for the consignee, and the the third is handed to the consignor when the shipment has been accepted. The consignor is responsible for the correctness of the particulars and statement concerning the cargo appearing in the air waybill. Each of the original parts of the air waybill has evidential value and possession of his part is a condition for the exercise by the consignor or consignee of his rights under the contract of carriage. Hague Protocol set forth in Article 9 that nothing in this. Convention prevents the issue of a negotiable air waybill, but Montreal Additional Protocol No. 4 deleted this article. All charges applicable to a shipment are payable in cash at the time of acceptance thereof by the carrier in case of a prepaid shipment or at the time of delivery thereof by the carrier in case of a collect shipment. The carrier shall have lien the cargo for unpaid charges and, in the event of non-payment thereof, shall have the right to dispose of the cargo at public or private sale and pay itself out of the proceeds of such sale any and all such amounts. In conclusion, the Warsaw Convention System has the character of ambiguity in various respects, not only in the part of the forms of documents but also in conditions of contract. Accordingly, the following propositions might be considered: (1) If the carrier does not obey the orders of the consignor for the disposition of the goods without proper reasons, he will be liable strictly for any damage which may be caused thereby to the cargo owner. The special agreement and carrier's conditions of carriage which limit unreasonably the consignor's right of disposition of the goods will be nullified. (2) The instrument of the Warsaw Convention System which is not yet in force(Montreal Additional Protocol No. 4) would considerably simplfy the processing and keeping of computerized records of the carriage. Until this instrument enters into force, the airlines will be faced with practical problems preventing them to substitute computerized data processing techniques for the formal issuance of the documents. Accordingly, Montreal Additional Protocol No. 4 should become effective as soon as posisble. From a practical point of view in the international trade, the issuance of negotiable air waybill should be permitted for the security of the bank.

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Predicting the Performance of Recommender Systems through Social Network Analysis and Artificial Neural Network (사회연결망분석과 인공신경망을 이용한 추천시스템 성능 예측)

  • Cho, Yoon-Ho;Kim, In-Hwan
    • Journal of Intelligence and Information Systems
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    • v.16 no.4
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    • pp.159-172
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    • 2010
  • The recommender system is one of the possible solutions to assist customers in finding the items they would like to purchase. To date, a variety of recommendation techniques have been developed. One of the most successful recommendation techniques is Collaborative Filtering (CF) that has been used in a number of different applications such as recommending Web pages, movies, music, articles and products. CF identifies customers whose tastes are similar to those of a given customer, and recommends items those customers have liked in the past. Numerous CF algorithms have been developed to increase the performance of recommender systems. Broadly, there are memory-based CF algorithms, model-based CF algorithms, and hybrid CF algorithms which combine CF with content-based techniques or other recommender systems. While many researchers have focused their efforts in improving CF performance, the theoretical justification of CF algorithms is lacking. That is, we do not know many things about how CF is done. Furthermore, the relative performances of CF algorithms are known to be domain and data dependent. It is very time-consuming and expensive to implement and launce a CF recommender system, and also the system unsuited for the given domain provides customers with poor quality recommendations that make them easily annoyed. Therefore, predicting the performances of CF algorithms in advance is practically important and needed. In this study, we propose an efficient approach to predict the performance of CF. Social Network Analysis (SNA) and Artificial Neural Network (ANN) are applied to develop our prediction model. CF can be modeled as a social network in which customers are nodes and purchase relationships between customers are links. SNA facilitates an exploration of the topological properties of the network structure that are implicit in data for CF recommendations. An ANN model is developed through an analysis of network topology, such as network density, inclusiveness, clustering coefficient, network centralization, and Krackhardt's efficiency. While network density, expressed as a proportion of the maximum possible number of links, captures the density of the whole network, the clustering coefficient captures the degree to which the overall network contains localized pockets of dense connectivity. Inclusiveness refers to the number of nodes which are included within the various connected parts of the social network. Centralization reflects the extent to which connections are concentrated in a small number of nodes rather than distributed equally among all nodes. Krackhardt's efficiency characterizes how dense the social network is beyond that barely needed to keep the social group even indirectly connected to one another. We use these social network measures as input variables of the ANN model. As an output variable, we use the recommendation accuracy measured by F1-measure. In order to evaluate the effectiveness of the ANN model, sales transaction data from H department store, one of the well-known department stores in Korea, was used. Total 396 experimental samples were gathered, and we used 40%, 40%, and 20% of them, for training, test, and validation, respectively. The 5-fold cross validation was also conducted to enhance the reliability of our experiments. The input variable measuring process consists of following three steps; analysis of customer similarities, construction of a social network, and analysis of social network patterns. We used Net Miner 3 and UCINET 6.0 for SNA, and Clementine 11.1 for ANN modeling. The experiments reported that the ANN model has 92.61% estimated accuracy and 0.0049 RMSE. Thus, we can know that our prediction model helps decide whether CF is useful for a given application with certain data characteristics.

Quantitative evaluation of collapse hazard levels of tunnel faces by interlinked consideration of face mapping, design and construction data: focused on adaptive weights (막장관찰 및 설계/시공자료가 연계 고려된 터널막장 붕괴 위험도의 정량적 산정: 가변형 가중치 중심으로)

  • Shin, Hyu-Soung;Lee, Seung-Soo;Kim, Kwang-Yeom;Bae, Gyu-Jin
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.15 no.5
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    • pp.505-522
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    • 2013
  • Previously, a new concept of indexing methodology has been proposed for quantitative assessment of tunnel collapse hazard level at each tunnel face with respect to the given geological data, design condition and the corresponding construction activity (Shin et al, 2009a). In this paper, 'linear' model, in which weights of influence factors are invariable, and 'non-linear' model, in which weights of influence factors are variable, are taken into account with some examples. Then, the 'non-linear' model is validated by using 100 tunnel collapse cases. It appears that 'non-linear' model allows us to have adapted weight values of influence factors to characteristics of given tunnel site. In order to make a better understanding and help for an effective use of the system, a series of operating processes of the system are built up. Then, by following the processes, the system is applied to a real-life tunnel project in very weak and varying ground conditions. Through this approach, it would be quite apparent that the tunnel collapse hazard indices are determined by well interlinked consideration of face mapping data as well as design/construction data. The calculated indices seem to be in good agreement with available electric resistivity distribution and design/construction status. In addition, This approach could enhance effective usage of face mapping data and lead timely and well corresponding field reactions to situation of weak tunnel faces.

The Trend of Aviation Terrorism in the 4th Industrial Revolution Period and the Development Direction for Domestic Counter Terrorism of Aviation (제4차 산업혁명 시대의 항공 테러리즘 양상 및 국내 항공테러 대응체계 발전방향)

  • Hwang, Ho-Won;Kim, Seung-Woo
    • The Korean Journal of Air & Space Law and Policy
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    • v.32 no.2
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    • pp.155-188
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    • 2017
  • On the one hand, the 4th Industrial Revolution provides a positive opportunity to build a new civilization paradigm for mankind. However, on the other hand, due to the 4th Industrial Revolution, artificial intelligence such as 'Goggle Alpha Go' revolutionized and even the human ability was replaced with a 'Silicon Chip' as the opportunity to communicate decreases, the existence of human beings is weakened. And there is a growing concern that the number of violent crimes, such as psychopath, which hunts humans as games, will increase. Moreover, recent international terrorism is being developed in a form similar to 'Psychopathic Violent-Crime' that indiscriminately attacks innocent people. So, the probability that terrorist organizations abuse the positive effects provided by the Fourth Industrial Revolution as means of terrorism is increasing. Therefore, the paradigm of aviation terrorism is expected to change in a way that attacks airport facilities and users rather than aircraft. Because airport facilities are crowded, and psychopathic terrorists are easily accessible. From this point of view, our counter terrorism system of aviation has many weak points in various aspects such as: (1) limitations of counter-terrorism center (2) inefficient on-site command and control system (3) separated organization for aviation security consultation (4) dispersed information collection function in government (5) vulnerable to cyber attack (6) lack of international cooperation network for aviation terrorism. Consequently, it is necessary to improve the domestic counter terrorism system of aviation so as to preemptively respond to the international terrorism. This study propose the following measures to improve the aviation security system by (1) create 'Aviation Special Judicial Police' (2) revise the anti-terrorism law and aviation security law (3) Strengthening the ability respond to terrorism in cyberspace (4) building an international cooperation network for aviation terrorism.

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PST Member Behavior Analysis Based on Three-Dimensional Finite Element Analysis According to Load Combination and Thickness of Grouting Layer (하중조합과 충전층 두께에 따른 3차원 유한요소 해석에 의한 PST 부재의 거동 분석)

  • Seo, Hyun-Su;Kim, Jin-Sup;Kwon, Min-Ho
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.22 no.6
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    • pp.53-62
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    • 2018
  • Follofwing the accelerating speed-up of trains and rising demand for large-volume transfer capacity, not only in Korea, but also around the world, track structures for trains have been improving consistently. Precast concrete slab track (PST), a concrete structure track, was developed as a system that can fulfil new safety and economic requirements for railroad traffic. The purpose of this study is to provide the information required for the development and design of the system in the future, by analyzing the behavior of each structural member of the PST system. The stress distribution result for different combinations of appropriate loads according to the KRL-2012 train load and KRC code was analyzed by conducting a three-dimensional finite element analysis, while the result for different thicknesses of the grouting layer is also presented. Among the structural members, the largest stress took place on the grouting layer. The stress changed sensitively following the thickness and the combination of loads. When compared with a case of applying only a vertical KRL-2012 load, the stress increased by 3.3 times and 14.1 times on a concrete panel and HSB, respectively, from the starting load and temperature load. When the thickness of the grouting layer increased from 20 mm to 80 mm, the stress generated on the concrete panel decreased by 4%, while the stress increased by 24% on the grouting layer. As for the cracking condition, tension cracking was caused locally on the grouting layer. Such a result indicates that more attention should be paid to the flexure and tension behavior from horizontal loads rather than from vertical loads when developing PST systems. In addition, the safety of each structural member must be ensured by maintaining the thickness of the grouting layer at 40 mm or more.