• The Korean Journal of Malacology
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• 제27권2호
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• pp.115-119
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• 2011

To establish technical development for artificial seed production, growth and survival for early young spats of the hard clam, Meretrix petechialis, were investigated by breeding methods. Adult clams were collected at Hasa-ri, Baeksu-eup, Yeonggwang-gun, Jeollanam-do on July 13, 2010, and then transported to the indoor aquarium at the laboratory. Eggs which were taken from mother clams, were inseminated, and after they were fertilized in the aquarium, 60 million bottom-clinging spats ($198{\pm}12{\mu}m$ in shell length) were produced and bred. The breeding experiments were carried out from July 16 to October 4, 2010 for 80 days. The methods of sand box, sand bottom circulation filter, inclosing net, floor were used for the breeding experiments, and the experimental condition of sea water temperature for larvae were at 25, 28, 31, $34^{\circ}C$. Four marine cultured food organisms were used for this study as follows: Isochrysis galbana, Chaetoceros gracilis, Phaeodactylum tricornutum, Tetraselmis tetrathele. According to the experimental conditions, experimental groups of the spats in the early stage were investigated the growth rate and the survival. As the result, the method of the inclosing net section was the fastest (grew up to $2.64{\pm}0.59{\mu}m$ in shell length), followed by sandbox ($2.59{\pm}0.64{\mu}m$, bottom circulating filter ($2.56{\pm}0.52{\mu}m$), and floor ($2.52{\pm}0.56{\mu}m$). The survival was the highest in the experimental condition of sandbox (35.9%), followed by floor (34.6%), bottom circulating filter (29.5%), and inclosing net (9.3%). Eexperimental condition of water temperature of $34^{\circ}C$ showed the fastest growth rate (grew up to $2.70{\pm}0.76{\mu}m$ in shell length), and showed the latest growth rate (grew up to $2.45{\pm}0.41{\mu}m$ in shell length) at $25^{\circ}C$. The survival (%) was the highest under the water temperature conditions at $31^{\circ}C$, and showed the lowest (14.2%) at $34.^{\circ}C$. The growth rate of the experimental group fed the mixture live food was the fastest with shell length $2.52{\pm}0.66{\mu}m$, and that of experimental group fed P. tricornutum showed the latest (grew up to $2.29{\pm}0.43{\mu}m$ in shell length). The survival was the highest (36.9%) under the experiment condition fed mixture live food and experimental group fed T. tetrathele showed the lowest rate (16.2%).

• Journal of Fisheries and Marine Sciences Education
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• 제3권2호
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• pp.47-72
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• 1991

To obtain the principal data for useful treatment and processing of Korean geoduck (Panope japonica A. ADAMS) which inhabit mostly at Dong-Hae coastal area in Korea, changes of $NH_2$-N, TMAO, TMA, total creatinine, protein composition and fatty acid composition in raw and blanched geoduck muscle during storage at $-20^{\circ}C$ were investigated. In addition, its chemical composition variation in the whole year was elucidated. The moisture content in geoduck muscle meat was 78.1% to 82% in the whole year. Particularly, in July its moisture content was maximum as 82% and in September minimum as 78.1%. Crude protein was in the range of 12.3-16.4%, crude lipid the average was 1.5%, crude ash on the average was 1.4%. The abundant fatty acids in geoduck muscle oil were $C_{16}$ : 0, $C_{16}$ : 1, $C_{18}$ : 0, $C_{18}$ : 1, $C_{20}$ : 5, and $C_{22}$ : 6 acids. During storage at $-20^{\circ}C$, content of unsaturated fatty acid such as eicosapentaenoic acid (EPA, $C_{20}$ : 5) and docosahexaenoic acid (DHA, $C_{22}$ : 6)in raw geoduck muscle decreased somewhat and the raw geoduck was slightly oxidized. Trimethylamine (TMA), volatile basic nitrogen (VBN)and $NH_2$-N of raw muscle increased compared to blanched muscle. Trimethylamine oxide (TMAO) was slightly decreased during the storage period. The muscle protein was approximately composed of 37% sarcoplasmic, 29% myofibrillar, 22% alkali soluble, and 12% stroma protein. Among several proteins, myofibrillar protein content decreased mostly, while the alkali-soluble and stroma protein content increased slightly during storage at $-20^{\circ}C$.

• Korean Journal of Soil Science and Fertilizer
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• 제9권4호
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• pp.223-233
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• 1976

The potassium equilibrium activity ratio ($AR^k_e$) and energies of exchange for replacement of ca+Mg by K ($E_k$) were measured for seven paddy soils to investigate their correlations with the exchangeable K (Kex) and uptake of K at different growth stages of rice plant. It was found that $AR^k_e$ had highly significant correlations at 1% level with uptake of K at maximum tillering, heading and harvesting stages, and also with Kex in soils at maximum tillering stage. The larger $AR^k_e$ of soils, the more uptake of K by rice plant. The fact indicates that uptake of K by the plant can be characterized in terms of $AR^k_e$ or energy of exchange of soils. In aspect of energy of exchange, higher uptake of K and yield of grain were observed from -2500 to -3000 calories per chemical equivalent, representing suitable balances between K and Ca+Mg in soils. Low uptake of K was observed at the energies of exchange below -3500 calories per chemical equivalent, which were prevalent in the ordinary acidic soils. From the correlations between energy of exchange and Kex, it can be concluded that at least 0.37 meq. of exchangeable K should be existed in 100g of dried acidic soil to keep suitable balances of K and Ca+Mg. The result shown that application of K adsorbed zeolite to paddy soils increased $AR^k_e$ and consequently brought about higher K uptake and grain yield. Therefore, a reasonable way recommended to get good balance of exchangeable K in the soil is applying 1.7 tonns of K adsorbed zeolite containing 60kg $K_2O$ per hectare.

• Korean Journal of Soil Science and Fertilizer
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• 제44권6호
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• pp.1195-1206
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• 2011

This study was conducted to apply LCA (Life cycle assessment) methodology to lettuce (Lactuca sativa L.) production systems in Namyang-ju as a case study. Five lettuce growing farms with three different farming systems (two farms with organic farming system, one farm with a system without agricultural chemicals and two farms with conventional farming system) were selected at Namyangju city of Gyeonggi-province in Korea. The input data for LCA were collected by interviewing with the farmers. The system boundary was set at a cropping season without heating and cooling system for reducing uncertainties in data collection and calculation. Sensitivity analysis was carried out to find out the effect of type and amount of fertilizer and energy use on GHG (Greenhouse Gas) emission. The results of establishing GTG (Gate-to-Gate) inventory revealed that the quantity of fertilizer and energy input had the largest value in producing 1 kg lettuce, the amount of pesticide input the smallest. The amount of electricity input was the largest in all farms except farm 1 which purchased seedlings from outside. The quantity of direct field emission of $CO_2$, $CH_4$ and $N_2O$ from farm 1 to farm 5 were 6.79E-03 (farm 1), 8.10E-03 (farm 2), 1.82E-02 (farm 3), 7.51E-02 (farm 4) and 1.61E-02 (farm 5) kg $kg^{-1}$ lettuce, respectively. According to the result of LCI analysis focused on GHG, it was observed that $CO_2$ emission was 2.92E-01 (farm 1), 3.76E-01 (farm 2), 4.11E-01 (farm 3), 9.40E-01 (farm 4) and $5.37E-01kg\;CO_2\;kg^{-1}\;lettuce$ (farm 5), respectively. Carbon dioxide contribute to the most GHG emission. Carbon dioxide was mainly emitted in the process of energy production, which occupied 67~91% of $CO_2$ emission from every production process from 5 farms. Due to higher proportion of $CO_2$ emission from production of compound fertilizer in conventional crop system, conventional crop system had lower proportion of $CO_2$ emission from energy production than organic crop system did. With increasing inorganic fertilizer input, the process of lettuce cultivation covered higher proportion in $N_2O$ emission. Therefore, farms 1 and 2 covered 87% of total $N_2O$ emission; and farm 3 covered 64%. The carbon footprints from farm 1 to farm 5 were 3.40E-01 (farm 1), 4.31E-01 (farm 2), 5.32E-01 (farm 3), 1.08E+00 (farm 4) and 6.14E-01 (farm 5) kg $CO_2$-eq. $kg^{-1}$ lettuce, respectively. Results of sensitivity analysis revealed the soybean meal was the most sensitive among 4 types of fertilizer. The value of compound fertilizer was the least sensitive among every fertilizer imput. Electricity showed the largest sensitivity on $CO_2$ emission. However, the value of $N_2O$ variation was almost zero.

• Korean Journal of Soil Science and Fertilizer
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• 제42권1호
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• pp.46-52
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• 2009

Deposition of atmospheric N that is depleted in $^{15}N$ has shown to decrease N isotope ratio ($^{15}N/^{14}N$,expressed as ${\delta}^{15}N$) of forest samples such as tree rings, foliage, and total soil-N. However, its effect on ${\delta}^{15}N$ of mineral soil-N which is biologically active N pool has never been tested. In this study, ${\delta}^{15}N$ of mineral N($NH{_4}^+$ and $NO_3{^-}$) in forest soils from organic and two depths of mineral soil layers (0 to 20 cm and 20 to 40cm depth) of Pinus densiflora stands located at two distinct areas (rural and industrial areas) in southern Korea was analyzed to investigate if there is any difference in ${\delta}^{15}N$ of mineral N between these areas. We also evaluated potential N loss of the study sites using ${\delta}^{15}N$ of mineral N. Across the soil layers, the ${\delta}^{15}N$ of $NH{_4}^+$ ranged from +8.9 to +24.8‰ in the rural area and from +4.4 to +13.8‰ in the industrial area. Soils from organic layer (+4.4‰) and mineral layer between 0 and 20 cm (+13.8‰) of industrial area showed significantly lower ${\delta}^{15}N$ of $NH{_4}^+$ than those of rural area (+8.9 and +24.3‰, respectively), probably indicating the greater contribution of $^{15}N$-depleted $NH{_4}^+$ from atmospheric deposition to forest in the industrial area than in the rural area. Meanwhile, ${\delta}^{15}N$ of $NO_3{^-}$ was not different between the rural and industrial areas, probably because ${\delta}^{15}N$ of $NO_3{^-}$ is more likely to be altered by the N loss that causes $^{15}N$ enrichment of the remaining soil N pool. Compared with the ${\delta}^{15}N$ of soil mineral N reported by other studies (from -10.9 to +15.6‰ for $NH{_4}^+$ and -14.8 to +5.6‰ for $NO_3{^-}$), the ${\delta}^{15}N$ observed in our study was substantially high, suggesting that the study sites are more subject to the N loss. It was concluded that $NH{_4}^+$ rather than $NO_3{^-}$ can conserve the ${\delta}^{15}N$ signature of atmospheric N deposition in forest ecosystems.

• Korean Journal of Soil Science and Fertilizer
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• 제40권5호
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• pp.383-391
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• 2007

This study was conducted for an assessment through the estimation of soil loss by each catchment classified by soil catena. Ten catchments, which are Geumgang21, Namgang03, Dongjincheon, Gapyongcheon01, Gyongancheon02, Geumgang16, Byongsungcheon01, Daesincheon, Bukcheon02, Youngsangang08, were selected from the hydrologic unit map and the detailed soil digital map (1:25,000) for this study. The catchments like Geumgang21, Namgang03, Dongjincheon, Gapyongcheon01 and Gyongancheon02 were mainly composed with soils originated from gneiss. The catchments like Geumgang16, Byongsungcheon01, Daesincheon, Bukcheon02 and Youngsangang08 were mainly composed with soils originated from granites. The grades, which are divided into seven grades with A(very tolerable), B(tolerable), C(moderate), D(low), E(high), F(severe), G(very severe), of soil erosion estimated by USLE in catchments were distributed in most A and B because of paddy land and forestry. In detailed, the soil erosion grade of catchments mainly distributing soils originated from gneiss showed more the distribution of B and C than it of catchments mainly distributing soils originated from granites. The reason of results would be derived from topographic characteristics of soils originated from gneiss located at mountainous. The soil loss according to soil catena linked with Songsan and Jigok series, which are soils originated from gneiss was calculated with $7.66ton\;ha^{-1}\;yr^{-1}$. The soil loss of Geumgang16, Byongsungcheon01, Daesincheon, Bukcheon02 which have the soil catena linked with Samgak and Sangju soil series originated from granite, was calculated with $5.55ton\;ha^{-1}\;yr^{-1}$. The soil loss of Youngsangang08 which have the soil catena linked with Songjung and Baeksan soil series originated from granite was calculated with $9.6ton\;ha^{-1}\;yr^{-1}$, but the conclusion on soil loss in this kind of soil catena would be drawn from the analysis of more catchments. In conclusion, the results of this study inform that the classification of soil catena by catchments and estimation of soil loss according to soil catena would be effective for analysis on the grade of non-point pollution by soil erosion in a catchment.

• (The) Research of the performance art and culture
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• 제36호
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• pp.441-471
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• 2018

East Coast Gut, Korean shamanism ritual on its east coastal area, is a Gut held in fishing villages alongside Korean east coastal area from Goseong area in Gangwon-Do to Busan area. East Coast Gut is performed in a series mainly by a successor shaman, Korean shaman, who hasn't received any spiritual power from a God, and the implications of this thesis lie in that we look over the learning aspects of Seokchool Kim shaman group among other East Coast Gut successor shaman groups after dividing it into 2 categories, successor shaman and learner shaman and based upon this, we reveal the meaning of the learning aspects of East Coast Gut. For successor shamans, home means the field of education. Since they are little, they chased Gut events performing dance in a series to accumulate onsite experiences. However, in the families of successor shamans that have passed their shaman work down from generation to generation, their descendents didn't inherit shaman work any longer, which changed the way of succession and learning of shaman work. Since 1980's, Gut has been officially acknowledged as a kind of general art embracing songs, dance and music and designated as a cultural asset of the state and each city and province, and at art universities, it was adopted as a required course for its related major, which caused new learner shamans who majored in shamanism to emerge. These learner shamans are taking systematical succession lessons on the performance skills of East Coast Byeolshin Gut at universities, East Coast Byeolshin Gut preservation community, any places where Guts are held and etc.. As changes along time, the successor shamans accepted the learner shamans to pass shaman work down and changes appeared in the notion of towners who accept the performer groups of Gut and Gut itself. Unlike the past, as Gut has been acknowledged as the origin of Korean traditional arts and as the product of compresensive learning on songs, dance and music and it was designated as a national intangible cultural asset, shaman's social status and personal pride and dignity has become very high. As shaman has become positioned as the traditional artist getting both national and international recognition unlike its past image of getting despised, at the site of Gut event or even in the relation with towners, their status and the treatment they get became far different. Even towners, along with shift in shaman groups' generation, take position to acknowledge and accept the addition of new learning elements unlike the past. Even in every town, rather than just insisting on the type or the event purpose of traditional Gut, they think over on the type of festival and the main direction of a variety of Guts with which all of towners can mingle with each other. They are trying to find new meanings in the trend of changing Gut and the adaptation of new generation to this. In our reality of Gut events getting minimalized along with rapid change of times, East Coast Gut is still very actively performed in a series until now compared to Guts in other regions. This is because following the successor shamans who have struggled to preserve the East Coast Gut, the learner shamans are actively inflowing and the series performance groups preserve the origin of Gut and try hard to use Gut as art contents. Besides, the learner shamans systematically organize what they learned on shamanism from the successor shamans and get prepared and try to hand it down to descendents in the closest possible way to preserve its origin. In the future, East Coast Gut will be succeeded by the learner shamans from the last successor shamans to inherit its tradition and develop it to adapt to the times.

• The Korean Journal of Archival Studies
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• 제22호
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• pp.157-199
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• 2009

The organization for managing records and archives did not emerge together with the founding of the Chinese Communist Party. Such management became active with the establishment of the Department of Documents (文書科) and its affiliated offices overseeing reading and safekeeping of official papers, after the formation of the Central Secretariat(中央秘書處) in 1926. Improving the work of the Secretariat's organization became the focus of critical discussions in the early 1930s. The main criticism was that the Secretariat had failed to be cognizant of its political role and degenerated into a mere "functional organization." The solution to this was the "politicization of the Secretariat's work." Moreover, influenced by the "Rectification Movement" in the 1940s, the party emphasized the responsibility of the Resources Department (材料科) that extended beyond managing documents to collecting, organizing and providing various kinds of important information data. In the mean time, maintaining security with regard to composing documents continued to be emphasized through such methods as using different names for figures and organizations or employing special inks for document production. In addition, communications between the central political organs and regional offices were emphasized through regular reports on work activities and situations of the local areas. The General Secretary not only composed the drafts of the major official documents but also handled the reading and examination of all documents, and thus played a central role in record processing. The records, called archives after undergoing document processing, were placed in safekeeping. This function was handled by the "Document Safekeeping Office(文件保管處)" of the Central Secretariat's Department of Documents. Although the Document Safekeeping Office, also called the "Central Repository(中央文庫)", could no longer accept, beginning in the early 1930s, additional archive transfers, the Resources Department continued to strengthen throughout the 1940s its role of safekeeping and providing documents and publication materials. In particular, collections of materials for research and study were carried out, and with the recovery of regions which had been under the Japanese rule, massive amounts of archive and document materials were collected. After being stipulated by rules in 1931, the archive classification and cataloguing methods became actively systematized, especially in the 1940s. Basically, "subject" classification methods and fundamental cataloguing techniques were adopted. The principle of assuming "importance" and "confidentiality" as the criteria of management emerged from a relatively early period, but the concept or process of evaluation that differentiated preservation and discarding of documents was not clear. While implementing a system of secure management and restricted access for confidential information, the critical view on providing use of archive materials was very strong, as can be seen in the slogan, "the unification of preservation and use." Even during the revolutionary movement and wars, the Chinese Communist Party continued their efforts to strengthen management and preservation of records & archives. The results were not always desirable nor were there any reasons for such experiences to lead to stable development. The historical conditions in which the Chinese Communist Party found itself probably made it inevitable. The most pronounced characteristics of this process can be found in the fact that they not only pursued efficiency of records & archives management at the functional level but, while strengthening their self-awareness of the political significance impacting the Chinese Communist Party's revolution movement, they also paid attention to the value possessed by archive materials as actual evidence for revolutionary policy research and as historical evidence of the Chinese Communist Party.

• Korean Journal of Environment and Ecology
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• 제33권2호
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• pp.202-215
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• 2019

This study was conducted to investigate the spawning preference of the Acheilognathinae fishes in relation to the shell size of host mussels after identifying the species of eggs and fries in the host mussel using our recently developed RFLP (Restriction Fragment Length Polymorphism) molecular marker at four sites [Hongcheon Naechoncheon (HN) and Deokchicheon (HD) from the North Han River basin and Jeongseon Goljicheon (JG) and Joyanggang (JJ) from the South Han River] in South Korea during May in each year between 2015 and 2018. The Acheilognathinae fish observed in the studied sites included one species (Acheilognathus signifer) in HN and JG, three species (Rhodeus uyekii, A. signifer, and Acheilognathus yamatsutae) in HD, and two species (A. signifer and Acheilognathus yamatsutae) in JJ, and we collected 982 host mussels (Unio douglasiae sinuolatus) that inhabited in all four sites. Using the RFLP molecular marker, we confirmed 46 eggs and fry of the Acheilognathinae fish (454 A. signifer, 43 Acheilognathus yamatsutae, and 149 Acheilognathus yamatsutae) in Unio douglasiae sinuolatus (N=163; 16.6%). We compare the average shell length, shell height, and shell width of mussels with [presence] eggs/fry and mussels without [absence] eggs/fry to examine the spawning preference according to the size of host mussels in each site. The results show that the shell length (1.98 mm), shell height (0.85 mm), and shell width (0.73 mm) of mussels with the eggs/fry were significantly larger (Mann-Whitney U test, P=0.002; difference=1.98 mm) than those of mussel without eggs/fry in HD where three species cohabitated. Although the shell length, shell height, and shell width of mussels with the eggs/fry were larger also in the other three sites, the difference was not statistically significant. In addition, we analyzed the mean number of spawned eggs and fry of each species and found $9.31{\pm}5.94$ R. uyekii, $2.86{\pm}2.45$ A.signifer, and $2.50{\pm}1.32$ A. yamatsutae. R. uyekii spawned 6.45-6.81 more eggs than A.signifer and A. yamatsutae on average per mussel, and it was statistically significant (Kruskal-Wallis test, P < 0.001). These findings indicate that the three species of Acheilognathinae fish tend to prefer larger mussels as their spawning hosts, and this tendency increases when the number of cohabitating bitterling fish species increases. Moreover, A.signifer and A. yamatsutae spawned a smaller number of eggs evenly in more host mussels while R. uyekii spawned many eggs on relatively fewer mussels. We found mussels (N=4) having the eggs/fry of two coexisting species, A. signifier and A. yamatsutae in HD and JJ where more than two bitterling fish species occurred. It suggests the interspecific competition taking place between the Acheilognathinae fishes for utilizing the same resource of mussels for spawning when two or more species cohabitate. This study is expected help to understand better the spawning patterns and reproductive ecology of the Acheilognathinae fishes, which will provide insightful information for advancing our understanding of their ecological relationships - mutualism or host-parasitism - with host mussels.

• Journal of Intelligence and Information Systems
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• 제25권2호
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• pp.39-55
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• 2019

Recently banks and large financial institutions have introduced lots of Robo-Advisor products. Robo-Advisor is a Robot to produce the optimal asset allocation portfolio for investors by using the financial engineering algorithms without any human intervention. Since the first introduction in Wall Street in 2008, the market size has grown to 60 billion dollars and is expected to expand to 2,000 billion dollars by 2020. Since Robo-Advisor algorithms suggest asset allocation output to investors, mathematical or statistical asset allocation strategies are applied. Mean variance optimization model developed by Markowitz is the typical asset allocation model. The model is a simple but quite intuitive portfolio strategy. For example, assets are allocated in order to minimize the risk on the portfolio while maximizing the expected return on the portfolio using optimization techniques. Despite its theoretical background, both academics and practitioners find that the standard mean variance optimization portfolio is very sensitive to the expected returns calculated by past price data. Corner solutions are often found to be allocated only to a few assets. The Black-Litterman Optimization model overcomes these problems by choosing a neutral Capital Asset Pricing Model equilibrium point. Implied equilibrium returns of each asset are derived from equilibrium market portfolio through reverse optimization. The Black-Litterman model uses a Bayesian approach to combine the subjective views on the price forecast of one or more assets with implied equilibrium returns, resulting a new estimates of risk and expected returns. These new estimates can produce optimal portfolio by the well-known Markowitz mean-variance optimization algorithm. If the investor does not have any views on his asset classes, the Black-Litterman optimization model produce the same portfolio as the market portfolio. What if the subjective views are incorrect? A survey on reports of stocks performance recommended by securities analysts show very poor results. Therefore the incorrect views combined with implied equilibrium returns may produce very poor portfolio output to the Black-Litterman model users. This paper suggests an objective investor views model based on Support Vector Machines(SVM), which have showed good performance results in stock price forecasting. SVM is a discriminative classifier defined by a separating hyper plane. The linear, radial basis and polynomial kernel functions are used to learn the hyper planes. Input variables for the SVM are returns, standard deviations, Stochastics %K and price parity degree for each asset class. SVM output returns expected stock price movements and their probabilities, which are used as input variables in the intelligent views model. The stock price movements are categorized by three phases; down, neutral and up. The expected stock returns make P matrix and their probability results are used in Q matrix. Implied equilibrium returns vector is combined with the intelligent views matrix, resulting the Black-Litterman optimal portfolio. For comparisons, Markowitz mean-variance optimization model and risk parity model are used. The value weighted market portfolio and equal weighted market portfolio are used as benchmark indexes. We collect the 8 KOSPI 200 sector indexes from January 2008 to December 2018 including 132 monthly index values. Training period is from 2008 to 2015 and testing period is from 2016 to 2018. Our suggested intelligent view model combined with implied equilibrium returns produced the optimal Black-Litterman portfolio. The out of sample period portfolio showed better performance compared with the well-known Markowitz mean-variance optimization portfolio, risk parity portfolio and market portfolio. The total return from 3 year-period Black-Litterman portfolio records 6.4%, which is the highest value. The maximum draw down is -20.8%, which is also the lowest value. Sharpe Ratio shows the highest value, 0.17. It measures the return to risk ratio. Overall, our suggested view model shows the possibility of replacing subjective analysts's views with objective view model for practitioners to apply the Robo-Advisor asset allocation algorithms in the real trading fields.