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International and domestic research trends in longitudinal connectivity evaluations of aquatic ecosystems, and the applicability analysis of fish-based models (수생태계 종적 연결성 평가를 위한 국내외 연구 현황 및 어류기반 종적 연속성 평가모델 적용성 분석)

  • Kim, Ji Yoon;Kim, Jai-Gu;Bae, Dae-Yeul;Kim, Hye-Jin;Kim, Jeong-Eun;Lee, Ho-Seong;Lim, Jun-Young;An, Kwang-Guk
    • Korean Journal of Environmental Biology
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    • v.38 no.4
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    • pp.634-649
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    • 2020
  • Recently, stream longitudinal connectivity has been a topic of investigation due to the frequent disconnections and the impact of aquatic ecosystems caused by the construction of small and medium-sized weirs and various artificial structures (fishways) directly influencing the stream ecosystem health. In this study, the international and domestic research trends of the longitudinal connectivity in aquatic ecosystems were evaluated and the applicability of fish-based longitudinal connectivity models used in developed countries was analyzed. For these purposes, we analyzed the current status of research on longitudinal connectivity and structural problems, fish monitoring methodology, monitoring approaches, longitudinal disconnectivity of fish movement, and biodiversity. In addition, we analyzed the current status and some technical limitations of physical habitat suitability evaluation, ecology-based water flow, eco-hydrological modeling for fish habitat connectivity, and the s/w program development for agent-based model. Numerous references, data, and various reports were examined to identify worldwide longitudinal stream connectivity evaluation models in European and non-European countries. The international approaches to longitudinal connectivity evaluations were categorized into five phases including 1) an approach integrating fish community and artificial structure surveys (two types input variables), 2) field monitoring approaches, 3) a stream geomorphological approach, 4) an artificial structure-based DB analytical approach, and 5) other approaches. the overall evaluation of survey methodologies and applicability for longitudinal stream connectivity suggested that the ICE model (Information sur la Continuite Ecologique) and the ICF model (Index de Connectivitat Fluvial), widely used in European countries, were appropriate for the application of longitudinal connectivity evaluations in Korean streams.

A Study on the Deok and Its Practice in Daesoon Thought: The Great Deok of Heaven and Earth of Kang Jeungsan (대순사상에 나타난 덕(德)과 그 실천수행 -강증산의 '천지대덕(天地大德)'과 관련하여-)

  • Joo, So-yeon;Ko, Nam-sik
    • Journal of the Daesoon Academy of Sciences
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    • v.38
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    • pp.1-46
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    • 2021
  • Since ancient times, the word Deok (德, virtue) has been used as a term in ethics. In the east, it originally meant 'to acquire (得),' and during the warring states period, it was used to indicate 'personality' or 'value;' especially for political leaders. Then, in Confucianism, the word Deok developed into an ethical term suggesting that people should acquire Deok in their action so as to achieve human perfection. In Daesoon Thought, Deok originates from the Dao, and the two are close in the same manner that Yin and Yang are close and interrelated. The Dao of Daesoon Thought indicates the Great Dao of Heaven and Earth, which Gucheon Sangje had opened when he performed his Gongbu (holy work) at Daewonsa Temple, is such that the Great Deok was divided into the Deok of Heaven, the Deok of Earth, and the Deok of Humanity. This allows for the realization of Deok in each of the Three Realms. Jo Jeongsan, the successor of Gucheon Sangje, said that he will inherit the Great Deok originated from the Great Dao and enlighten the world to the Dao. The cause of the accumulation of grievances in the Three Realms was due to the failure to sufficiently spread Deok throughout the Three Realms. The Later World is where Deok will be offered in its full extent as it was secured by the Cheonjigongsa (Reordering Works of Heaven and Earth) performed by Gucheon Sangje. However, as the main agent of spreading Deok is the heart-mind, humans need to cultivate their heart-mind in the correct way. When humans finally become Dotong-gunja (beings who are perfectly unified with the Dao) and generously practice Deok in the world, there will be no grievances anywhere in the Three Realms. There are four ways of practicing Deok: Deok by caring for life, Eondeok (Deok of speech), Gongdeok (practicing meritorious Deok), and Podeok (spreading of Deok) to the world. Practicing the Deok by caring for life is to save and protect living beings based on the spirit of Jesaenguise (saving lives and curing the world). Eondeok is practiced when people speak to others in a positive way that fosters widespread goodness based on the spirit of Sangsaeng (mutual beneficence). When people perform Gongdeok they will be rewarded for their actions. Podeok can be realized when the followers of Sangje spread the Great Dao of Heaven and Earth based on the teachings of Daesoon Thought.

Adaptive Image Rescaling for Weakly Contrast-Enhanced Lesions in Dedicated Breast CT: A Phantom Study (약하게 조영증강된 병변의 유방 전용 CT 영상의 대조도 개선을 위한 적응적 영상 재조정 방법: 팬텀 연구)

  • Bitbyeol Kim;Ho Kyung Kim;Jinsung Kim;Yongkan Ki;Ji Hyeon Joo;Hosang Jeon;Dahl Park;Wontaek Kim;Jiho Nam;Dong Hyeon Kim
    • Journal of the Korean Society of Radiology
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    • v.82 no.6
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    • pp.1477-1492
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    • 2021
  • Purpose Dedicated breast CT is an emerging volumetric X-ray imaging modality for diagnosis that does not require any painful breast compression. To improve the detection rate of weakly enhanced lesions, an adaptive image rescaling (AIR) technique was proposed. Materials and Methods Two disks containing five identical holes and five holes of different diameters were scanned using 60/100 kVp to obtain single-energy CT (SECT), dual-energy CT (DECT), and AIR images. A piece of pork was also scanned as a subclinical trial. The image quality was evaluated using image contrast and contrast-to-noise ratio (CNR). The difference of imaging performances was confirmed using student's t test. Results Total mean image contrast of AIR (0.70) reached 74.5% of that of DECT (0.94) and was higher than that of SECT (0.22) by 318.2%. Total mean CNR of AIR (5.08) was 35.5% of that of SECT (14.30) and was higher than that of DECT (2.28) by 222.8%. A similar trend was observed in the subclinical study. Conclusion The results demonstrated superior image contrast of AIR over SECT, and its higher overall image quality compared to DECT with half the exposure. Therefore, AIR seems to have the potential to improve the detectability of lesions with dedicated breast CT.

The detection of collapsible airways contributing to airflow limitation (기류 제한에 영향을 미치는 허탈성 기도의 분석)

  • Kim, Yun Seong;Park, Byung Gyu;Lee, Kyong In;Son, Seok Man;Lee, Hyo Jin;Lee, Min Ki;Son, Choon Hee;Park, Soon Kew
    • Tuberculosis and Respiratory Diseases
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    • v.43 no.4
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    • pp.558-570
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    • 1996
  • Background : The detection of Collapsible airways has important therapeutic implications in chronic airway disease and bronchial asthma. The distinction of a purely collapsible airways disease from that of asthma is important because the treatment of the dormer may include the use of pursed lip breathing or nasal positive pressure ventilation whereas in the latter, pharmacologic approaches are used. One form of irreversible airflow limitation is collapsible airways, which has been shown to be a Component of asthma or to emphysema, it can be assessed by the volume difference between what exits the lung as determined by a spirometer and the volume compressed as measured by the plethysmography. Method : To investigate whether volume difference between slow and forced vital Capacity(SVC-FVC) by spirometry may be used as a surrogate index of airway collapse, we examined pulmonary function parameters before and after bronchodilator agent inhalation by spirometry and body plethysmography in 20 cases of patients with evidence of airflow limitation(chronic obstructive pulmonary disease 12 cases, stable bronchial asthma 7 cases, combined chronic obstructive pulmonary disease with asthma 1 case) and 20 cases of normal subjects without evidence of airflow limitation referred to the Pusan National University Hospital pulmonary function laboratory from January 1995 to July 1995 prospectively. Results : 1) Average and standard deviation of age, height, weight of patients with airflow limitation was $58.3{\pm}7.24$(yr), $166{\pm}8.0$(cm), $59.0{\pm}9.9$(kg) and those of normal subjects was $56.3{\pm}12.47$(yr), $165.9{\pm}6.9$(cm), $64.4{\pm}10.4$(kg), respectively. The differences of physical characteristics of both group were not significant statistically and male to female ratio was 14:6 in both groups. 2) The difference between slow vital capacity and forced vital capacity was $395{\pm}317ml$ in patients group and $154{\pm}176ml$ in normal group and there was statistically significance between two groups(p<0.05). Sensitivity and specificity were most higher when the cut-off value was 208ml. 3) After bronchodilator inhalation, reversible airway obstructions were shown in 16 cases of patients group, 7 cases of control group(p<0.05) by spirometry or body plethysmography d the differences of slow vital capacity and forced vital capacity in bronchodilator response group and nonresponse group were $300.4{\pm}306ml$, $144.7{\pm}180ml$ and this difference was statistically significant. 4) The difference between slow vital capacity and forced vital capacity before bronchodilator inhalation was correlated with airway resistance before bronchodilator(r=0.307 p=0.05), and the difference between slow vital capacity and forced vital capacity after bronchodilator was correlated with difference between slow vital capacity and forced vital capacity(r=0.559 p=0.0002), thoracic gas volume(r=0.488 p=0.002) before bronchodilator and airway resistance(r=0.583 p=0.0001), thoracic gas volume(r=0.375 p=0.0170) after bronchodilator, respectively. 5) The difference between slow vital capacity and forced vital capacity in smokers and nonsmokers was $257.5{\pm}303ml$, $277.5{\pm}276ml$, respectively and this difference did not reach statistical significance(p>0.05). Conclusion : The difference between slow vital capacity and forced vital capacity by spirometry may be useful for the detection of collapsible airway and may help decision making of therapeutic plans.

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Dynamic Limit and Predatory Pricing Under Uncertainty (불확실성하(不確實性下)의 동태적(動態的) 진입제한(進入制限) 및 약탈가격(掠奪價格) 책정(策定))

  • Yoo, Yoon-ha
    • KDI Journal of Economic Policy
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    • v.13 no.1
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    • pp.151-166
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    • 1991
  • In this paper, a simple game-theoretic entry deterrence model is developed that integrates both limit pricing and predatory pricing. While there have been extensive studies which have dealt with predation and limit pricing separately, no study so far has analyzed these closely related practices in a unified framework. Treating each practice as if it were an independent phenomenon is, of course, an analytical necessity to abstract from complex realities. However, welfare analysis based on such a model may give misleading policy implications. By analyzing limit and predatory pricing within a single framework, this paper attempts to shed some light on the effects of interactions between these two frequently cited tactics of entry deterrence. Another distinctive feature of the paper is that limit and predatory pricing emerge, in equilibrium, as rational, profit maximizing strategies in the model. Until recently, the only conclusion from formal analyses of predatory pricing was that predation is unlikely to take place if every economic agent is assumed to be rational. This conclusion rests upon the argument that predation is costly; that is, it inflicts more losses upon the predator than upon the rival producer, and, therefore, is unlikely to succeed in driving out the rival, who understands that the price cutting, if it ever takes place, must be temporary. Recently several attempts have been made to overcome this modelling difficulty by Kreps and Wilson, Milgram and Roberts, Benoit, Fudenberg and Tirole, and Roberts. With the exception of Roberts, however, these studies, though successful in preserving the rationality of players, still share one serious weakness in that they resort to ad hoc, external constraints in order to generate profit maximizing predation. The present paper uses a highly stylized model of Cournot duopoly and derives the equilibrium predatory strategy without invoking external constraints except the assumption of asymmetrically distributed information. The underlying intuition behind the model can be summarized as follows. Imagine a firm that is considering entry into a monopolist's market but is uncertain about the incumbent firm's cost structure. If the monopolist has low cost, the rival would rather not enter because it would be difficult to compete with an efficient, low-cost firm. If the monopolist has high costs, however, the rival will definitely enter the market because it can make positive profits. In this situation, if the incumbent firm unwittingly produces its monopoly output, the entrant can infer the nature of the monopolist's cost by observing the monopolist's price. Knowing this, the high cost monopolist increases its output level up to what would have been produced by a low cost firm in an effort to conceal its cost condition. This constitutes limit pricing. The same logic applies when there is a rival competitor in the market. Producing a high cost duopoly output is self-revealing and thus to be avoided. Therefore, the firm chooses to produce the low cost duopoly output, consequently inflicting losses to the entrant or rival producer, thus acting in a predatory manner. The policy implications of the analysis are rather mixed. Contrary to the widely accepted hypothesis that predation is, at best, a negative sum game, and thus, a strategy that is unlikely to be played from the outset, this paper concludes that predation can be real occurence by showing that it can arise as an effective profit maximizing strategy. This conclusion alone may imply that the government can play a role in increasing the consumer welfare, say, by banning predation or limit pricing. However, the problem is that it is rather difficult to ascribe any welfare losses to these kinds of entry deterring practices. This difficulty arises from the fact that if the same practices have been adopted by a low cost firm, they could not be called entry-deterring. Moreover, the high cost incumbent in the model is doing exactly what the low cost firm would have done to keep the market to itself. All in all, this paper suggests that a government injunction of limit and predatory pricing should be applied with great care, evaluating each case on its own basis. Hasty generalization may work to the detriment, rather than the enhancement of consumer welfare.

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INFLUENCES OF DRY METHODS OF RETROCAVITY ON THE APICAL SEAL (치근단 역충전와동의 건조방법이 폐쇄성에 미치는 영향)

  • Lee, Jung-Tae;Kim, Sung-Kyo
    • Restorative Dentistry and Endodontics
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    • v.24 no.1
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    • pp.166-179
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    • 1999
  • Apical sealing is essential for the success of surgical endodontic treatment. Root-end cavity is apt to be contaminated with moisture or blood, and is not always easy to be dried completely. The purpose of this study was to evaluate the influence of dry methods of retrocavity on the apical seal in endodontic surgery. Apical seal was investigated through the evaluation of apical leakage and adaptation of filling material over the cavity wall. To investigate the influence of various dry methods on the apical leakage, 125 palatal roots of extracted human maxillary molar teeth were used. The clinical crown of each tooth was removed at 10 mm from the root apex using a slow-speed diamond saw and water spray. Root canals of the all the specimens were prepared with step-back technique and filled with gutta-percha by lateral condensation method. After removing of the coronal 2 mm of filling material, the access cavities were closed with Cavit$^{(R)}$. Two coats of nail polish were applied to the external surface of each root. Apical three millimeters of each root was resected perpendicular to the long axis of the root with a diamond saw. Class I retrograde cavities were prepared with ultrasonic instruments. Retrocavities were washed with physiologic saline solution and dried with various methods or contaminated with human blood. Retrocavities were filled either with IRM, Super EBA or composite resin. All the specimens were immersed in 2% methylene blue solution for 7 days in an incubator at $37^{\circ}C$. The teeth were dissolved in 14 ml of 35% nitric acid solution and the dye present within the root canal system was returned to solution. The leakage of dye was quantitatively measured via spectrophotometric method. The obtained data were analysed statistically using one-way ANOVA and Duncan's Multiple Range Test. To evaluate the influence of various dry methods on the adaptation of filling material over the cavity wall, 12 palatal roots of extracted human maxillary molar teeth were used. After all the roots were prepared and filled, and retrograde cavities were made and filled as above, roots were sectioned longitudinally. Filling-dentin interface of cut surfaces were examined by scanning electron microscope. The results were as follows: 1. Cavities dried with paper point or compressed air showed less leakage than those dried with cotton pellet in Super EBA filled cavity (p<0.05). However, there was no difference between paper point- and compressed air-dried cavities. 2. When cavities were dried with compressed air, dentin-bonded composite resin-filled cavities showed less apical leakage than IRM- or Super EBA-filled ones (p<0.05). 3. Regardless of the filling material, cavities contaminated with human blood showed significantly more apical leakage than those dried with compressed air after saline irrigation (p<0.05). 4. Outer half of the cavity showed larger dentin-filling interface gap than inner half did when cavities were filled with IRM or Super EBA. 5. In all the filling material groups, cavities contaminated with blood or dried with cotton pellets only showed larger defects at the base of the cavity than ones dried with paper points or compressed air.

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Surgery Alone or Postoperative Adjuvant Radiotherapy in Rectal Cancer - With Respect to Survival, Pelvic Control, Prognostic Factor - (직장암에서 수술단독 또는 수술후 방사선치료 -생존율, 골반종양제어율, 예후인자를 중심으로-)

  • Nam, Taek-Keun;Ahn, Sung-Ja;Nah, Byung-Sik
    • Radiation Oncology Journal
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    • v.19 no.4
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    • pp.327-334
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    • 2001
  • Purpose : To find out the role of postoperative adjuvant radiotherapy in the treatment of rectal cancer by comparing survival, pelvic control, complication rate, and any prognostic factor between surgery alone and postoperative radiotherapy group. Materials and methods : From Feb. 1982 to Dec. 1996 total 212 patients were treated by radical surgery with or without postoperative radiotherapy due to rectal carcinoma of modified Astler-Coiler stage $B2\~C3$. Of them, 18 patients had incomplete radiotherapy and so the remaining 194 patients were the database analyzed in this study. One hundred four patients received postoperative radiotherapy and the other 90 patients had surgery only. Radiotherapy was peformed in the range of $39.6\~55.8\;Gy$ (mean: 49.9 Gy) to the whole pelvis and if necessary, tumor bed was boosted by $5.4\~10\;Gy$. Both survival and pelvic control rates were calculated by Kaplan-Meier method and their statistical significance was tested by Log-rank test. Multivariate analysis was peformed by Cox proportional hazards model. Results : 5-year actuarial survival rate (5YSR) and 5-year disease-free survival rate (5YDFSR) of entire patients were $53\%\;and\;49\%$, respectively. 5YSRs of surgery alone group and adjuvant radiotherapy group were $63\%\;vs\;45\%$, respectively (p=0.03). This difference is thought to reflect uneven distribution of stages between two treatment groups (p<0.05 by $\chi^2-test$) with more advanced disease patients in adjuvant radiotherapy group. 5YSRs of surgery alone vs adjuvant radiotherapy group in MAC B2+3, C1, C2+3 were $68\%\;vs\;55\%$ (p=0.09), $100\%\;vs\;100\%$, $40\%\;vs\;33\%$ (p=0.71), respectively. 5YDFSRs of surgery alone vs adjuvant radiotherapy group in above three stages were $65\%\;vs\;49\%$ (p=0.14), $100\%\;vs\;100\%$, $33\%\;vs\;31\%$ (p=0.46), respectively. 5-year pelvic control rate (5YPCR) of entire patients was $72.5\%$. 5YPCRs of surgery alone and adjuvant radiotherapy group were $71\%\;vs\;74\%$, respectively (p=0.41). 5YPCRs of surgery alone vs adjuvant radiotherapy group in B2+3, C1, C2+3 were $79\%\;vs\;75\%$ (p=0.88), $100\%\;vs\;100\%$, $44\%\;vs\;68\%$ (p=0.01), respectively. Multivariate analysis showed that only stage was significant factor affecting overall and disease-free survival in entire patients and also in both treatment groups. In view of pelvic control, stage and operation type were significant in entire patients and only stage in surgery alone group but in adjuvant radiotherapy group, operation type instead of stage was the only significant factor in multivariate analysis as a negative prognostic factor in abdominoperineal resection cases. Conclusion : Our retrospective study showed that postoperative adjuvant radiotherapy could improve the pelvic control in MAC C2+3 group. To improve both pelvic control and survival in all patients with MAC B2 or more, other treatment modality such as concurrent continuous infusion of 5-FU, which is the most standard agent, with radiotherapy should be considered.

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Neonatal Sepsis and Antimicrobial Susceptibilities in the Neonatal Intensive Care Unit and Nursery (신생아 패혈증의 원인 및 항생제 감수성)

  • Moon, Jin Hwa;Oh, Sung Hee;Kim, Hak Won;Moon, Su Jee;Choi, Tae Yeol
    • Pediatric Infection and Vaccine
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    • v.9 no.2
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    • pp.163-174
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    • 2002
  • Background : To delineate the changes in the causative agents of neonatal sepsis and their antimicrobial susceptibilities in the neonatal intensive care unit and nursery of Hanyang University Hospital during the past 10 years. Methods : Hospital records of 15,144 patients hospitalized at the NICU and nursery of Hanyang University Hospital from 1989 to 1998 were reviewed and neonates diagnosed of neonatal sepsis were sorted and included in the study. The study period was divided into Period A(the first 5 years) and Period B(the second 5 years) to analyse causative agents and their antimicrobial susceptibilities. Results : Neonatal sepsis was diagnosed in 170 patients(1.1%{Period A 1.2%, Period B 1.0%}) among the total of 15,144 inpatients. Two hundred isolates(Period A 109 isolates, Period B 91 isolates) were identified in 186 blood cultures(Period A 99 cultures, Period B 87 cultures) from 170 patients(Period A 91 patients, Period B 79 patients). The average age at the onset of the disease, when the initial blood culture was drawn, was 12.3 days old(Period A 8.8 days, Period B 16.3 days), and the proportion of the early onset disease was 34.7% in Period A and 23.0% in Period B, indicating that neonatal sepsis developed earlier during Period A. Among the isolated organisms including Gram positive bacteria[132(66.0%)], Gram negative bacteria [60(30.0%)], and fungi[8(4.0%)], coagulase negative Staphylococcus(CNS) was the most common organism(69/34.5%), followed by Staphylococcus aureus(36/18.0%), Klebsiella pneumoniae(17/8.5%), Enterococcus(12/6.0%), Enterobacter cloacae(8/4.0%), Escherichia coli(6/3.0%), and Pseudomonas aeruginosae(5/2.5%). The isolated fungi were Candida parapsilosis, Candida albicans, and Trichosporon pullulans. CNS, S. aureus and Acinetobacter baumannii were isolated more frequently in Period A compared to Period B. Antimicrobial susceptibilities of CNS and S. aureus to methicillin and the first generation cephalo sporins were decreased in Period B compare to Period A, those to aminoglycosides were increased in Period B, and vancomycin resistant strains were not identified. K. pneumoniae, Enterococcus, E. coli, and P. aeruginosa were isolated less frequently in Period B, compared to Period A. For K. pneumoniae, antimicrobial susceptibilities to the first generation cephalosporins were low in both Periods A and B, those to tobramycin and gentamicin were increased in Period B, and those to amikacin, ceftriaxone, and trimethoprim-sulfamethoxazole were high in both Periods A and B. Antimicrobial susceptibilities of Enterococcous to ampicillin, penicillin, and the first generation cephalosporins were decreased in Period B, but vancomycin resistant strains were not identified. Conclusion : The occurrence rate of neonatal sepsis during the past 10 years in the NICU and nursery of the Hanyang University hospital was 1.1%, and the most common causitive agents were CNS and S. aureus, to which the antimicrobial susceptibilities to the first line drugs decreased in the later half of the study period with no vancomycin resistant isolates identified. Group B Streptococcus known to be the most common agent causing neonatal sepsis was not identified, and K. pneumoniae was isolated more commonly during the later half of the study period without decreased antimicrobial susceptibilities.

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A study on Development Process of Fish Aquaculture in Japan - Case by Seabream Aquaculture - (일본 어류 양식업의 발전과정과 산지교체에 관한 연구 : 참돔양식업을 사례로)

  • 송정헌
    • The Journal of Fisheries Business Administration
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    • v.34 no.2
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    • pp.75-90
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    • 2003
  • When we think of fundamental problems of the aquaculture industry, there are several strict conditions, and consequently the aquaculture industry is forced to change. Fish aquaculture has a structural supply surplus in production, aggravation of fishing grounds, stagnant low price due to recent recession, and drastic change of distribution circumstances. It is requested for us to initiate discussion on such issue as “how fish aquaculture establishes its status in the coastal fishery\ulcorner, will fish aquaculture grow in the future\ulcorner, and if so “how it will be restructured\ulcorner” The above issues can be observed in the mariculture of yellow tail, sea scallop and eel. But there have not been studied concerning seabream even though the production is over 30% of the total production of fish aquaculture in resent and it occupied an important status in the fish aquaculture. The objectives of this study is to forecast the future movement of sea bream aquaculture. The first goal of the study is to contribute to managerial and economic studies on the aquaculture industry. The second goal is to identify the factors influencing the competition between production areas and to identify the mechanisms involved. This study will examine the competitive power in individual producing area, its behavior, and its compulsory factors based on case study. Producing areas will be categorized according to following parameters : distance to market and availability of transportation, natural environment, the time of formation of producing areas (leaderㆍfollower), major production items, scale of business and producing areas, degree of organization in production and sales. As a factor in shaping the production area of sea bream aquaculture, natural conditions especially the water temperature is very important. Sea bream shows more active feeding and faster growth in areas located where the water temperature does not go below 13∼14$^{\circ}C$ during the winter. Also fish aquaculture is constrained by the transporting distance. Aquacultured yellowtail is a mass-produced and a mass-distributed item. It is sold a unit of cage and transported by ship. On the other hand, sea bream is sold in small amount in markets and transported by truck; so, the transportation cost is higher than yellow tail. Aquacultured sea bream has different product characteristics due to transport distance. We need to study live fish and fresh fish markets separately. Live fish was the original product form of aquacultured sea bream. Transportation of live fish has more constraints than the transportation of fresh fish. Death rate and distance are highly correlated. In addition, loading capacity of live fish is less than fresh fish. In the case of a 10 ton truck, live fish can only be loaded up to 1.5 tons. But, fresh fish which can be placed in a box can be loaded up to 5 to 6 tons. Because of this characteristics, live fish requires closer location to consumption area than fresh fish. In the consumption markets, the size of fresh fish is mainly 0.8 to 2kg.Live fish usually goes through auction, and quality is graded. Main purchaser comes from many small-sized restaurants, so a relatively small farmer and distributer can sell it. Aquacultured sea bream has been transacted as a fresh fish in GMS ,since 1993 when the price plummeted. Economies of scale works in case of fresh fish. The characteristics of fresh fish is as follows : As a large scale demander, General Merchandise Stores are the main purchasers of sea bream and the size of the fish is around 1.3kg. It mainly goes through negotiation. Aquacultured sea bream has been established as a representative food in General Merchandise Stores. GMS require stable and mass supply, consistent size, and low price. And Distribution of fresh fish is undertook by the large scale distributers, which can satisfy requirements of GMS. The market share in Tokyo Central Wholesale Market shows Mie Pref. is dominating in live fish. And Ehime Pref. is dominating in fresh fish. Ehime Pref. showed remarkable growth in 1990s. At present, the dealings of live fish is decreasing. However, the dealings of fresh fish is increasing in Tokyo Central Wholesale Market. The price of live fish is decreasing more than one of fresh fish. Even though Ehime Pref. has an ideal natural environment for sea bream aquaculture, its entry into sea bream aquaculture was late, because it was located at a further distance to consumers than the competing producing areas. However, Ehime Pref. became the number one producing areas through the sales of fresh fish in the 1990s. The production volume is almost 3 times the production volume of Mie Pref. which is the number two production area. More conversion from yellow tail aquaculture to sea bream aquaculture is taking place in Ehime Pref., because Kagosima Pref. has a better natural environment for yellow tail aquaculture. Transportation is worse than Mie Pref., but this region as a far-flung producing area makes up by increasing the business scale. Ehime Pref. increases the market share for fresh fish by creating demand from GMS. Ehime Pref. has developed market strategies such as a quick return at a small profit, a stable and mass supply and standardization in size. Ehime Pref. increases the market power by the capital of a large scale commission agent. Secondly Mie Pref. is close to markets and composed of small scale farmers. Mie Pref. switched to sea bream aquaculture early, because of the price decrease in aquacultured yellou tail and natural environmental problems. Mie Pref. had not changed until 1993 when the price of the sea bream plummeted. Because it had better natural environment and transportation. Mie Pref. has a suitable water temperature range required for sea bream aquaculture. However, the price of live sea bream continued to decline due to excessive production and economic recession. As a consequence, small scale farmers are faced with a market price below the average production cost in 1993. In such kind of situation, the small-sized and inefficient manager in Mie Pref. was obliged to withdraw from sea bream aquaculture. Kumamoto Pref. is located further from market sites and has an unsuitable nature environmental condition required for sea bream aquaculture. Although Kumamoto Pref. is trying to convert to the puffer fish aquaculture which requires different rearing techniques, aquaculture technique for puffer fish is not established yet.

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Construction of Consumer Confidence index based on Sentiment analysis using News articles (뉴스기사를 이용한 소비자의 경기심리지수 생성)

  • Song, Minchae;Shin, Kyung-shik
    • Journal of Intelligence and Information Systems
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    • v.23 no.3
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    • pp.1-27
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    • 2017
  • It is known that the economic sentiment index and macroeconomic indicators are closely related because economic agent's judgment and forecast of the business conditions affect economic fluctuations. For this reason, consumer sentiment or confidence provides steady fodder for business and is treated as an important piece of economic information. In Korea, private consumption accounts and consumer sentiment index highly relevant for both, which is a very important economic indicator for evaluating and forecasting the domestic economic situation. However, despite offering relevant insights into private consumption and GDP, the traditional approach to measuring the consumer confidence based on the survey has several limits. One possible weakness is that it takes considerable time to research, collect, and aggregate the data. If certain urgent issues arise, timely information will not be announced until the end of each month. In addition, the survey only contains information derived from questionnaire items, which means it can be difficult to catch up to the direct effects of newly arising issues. The survey also faces potential declines in response rates and erroneous responses. Therefore, it is necessary to find a way to complement it. For this purpose, we construct and assess an index designed to measure consumer economic sentiment index using sentiment analysis. Unlike the survey-based measures, our index relies on textual analysis to extract sentiment from economic and financial news articles. In particular, text data such as news articles and SNS are timely and cover a wide range of issues; because such sources can quickly capture the economic impact of specific economic issues, they have great potential as economic indicators. There exist two main approaches to the automatic extraction of sentiment from a text, we apply the lexicon-based approach, using sentiment lexicon dictionaries of words annotated with the semantic orientations. In creating the sentiment lexicon dictionaries, we enter the semantic orientation of individual words manually, though we do not attempt a full linguistic analysis (one that involves analysis of word senses or argument structure); this is the limitation of our research and further work in that direction remains possible. In this study, we generate a time series index of economic sentiment in the news. The construction of the index consists of three broad steps: (1) Collecting a large corpus of economic news articles on the web, (2) Applying lexicon-based methods for sentiment analysis of each article to score the article in terms of sentiment orientation (positive, negative and neutral), and (3) Constructing an economic sentiment index of consumers by aggregating monthly time series for each sentiment word. In line with existing scholarly assessments of the relationship between the consumer confidence index and macroeconomic indicators, any new index should be assessed for its usefulness. We examine the new index's usefulness by comparing other economic indicators to the CSI. To check the usefulness of the newly index based on sentiment analysis, trend and cross - correlation analysis are carried out to analyze the relations and lagged structure. Finally, we analyze the forecasting power using the one step ahead of out of sample prediction. As a result, the news sentiment index correlates strongly with related contemporaneous key indicators in almost all experiments. We also find that news sentiment shocks predict future economic activity in most cases. In almost all experiments, the news sentiment index strongly correlates with related contemporaneous key indicators. Furthermore, in most cases, news sentiment shocks predict future economic activity; in head-to-head comparisons, the news sentiment measures outperform survey-based sentiment index as CSI. Policy makers want to understand consumer or public opinions about existing or proposed policies. Such opinions enable relevant government decision-makers to respond quickly to monitor various web media, SNS, or news articles. Textual data, such as news articles and social networks (Twitter, Facebook and blogs) are generated at high-speeds and cover a wide range of issues; because such sources can quickly capture the economic impact of specific economic issues, they have great potential as economic indicators. Although research using unstructured data in economic analysis is in its early stages, but the utilization of data is expected to greatly increase once its usefulness is confirmed.