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A Study of the Images of General Supers and a Department Store in a Local City (지방도시에 입점하고 있는 종합슈퍼와 백화점에 대한 점포이미지 비교 분석)

  • Kim, Chang-Gon
    • Journal of Distribution Science
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    • v.10 no.6
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    • pp.17-26
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    • 2012
  • Suncheon is a city comprising a rural and urban area, where there are four types of large stores. Studies have shown that there are too many large stores serving the local population of just 300,000. However, geographically, Suncheon is located at a transportation hub that borders the cities of Gwangyang and Yeosu as well as the local counties of Boseong and Gurae. Residents of these areas can reach these shopping stores within an hour's drive. Thus, the managers of these four stores regard residents in these areas as their valued customers and endeavor to create a differentiated image among them. In this study, 13 different images were used to determine the public's opinions and feelings towards these stores and the differences were analyzed. The store images measured overall store impression, diversity of the product, the quality of products displayed at the store, accessibility, the atmosphere, service to the customers, and so on. These images are evaluated subjectively by each customer and are major factors in them deciding to revisit the stores. The 13 images are classified into five main categories and further classified into 13 sub-categories. Three kinds of factor images were extracted from the store images in the five main categories by factor analysis using SPSS Ver. 19. The first factor image was extracted from the images of convenience, atmosphere, and service in the main categories and is called a sub-service factor for the store in this study. Accessibility to the store was classified as a convenience image in the main category and was extracted as a common factor along with diversity and the price of goods. These differences are expected according to the store location, that is, the difference between stores located in a large city and those in a small local city, and depending on the nature of survey respondents. The result shows that there is a significant difference between the stores' images with regard to accessibility, the price of products, brand image, and lighting/sound image. This study has the following limitations. First, the survey sample was restricted to residents of a small local city that includes rural and urban populations. The differences between the store images regarding traffic and accessibility are factored by store location, whether they are located within a large or a small city as well as the economic situation of these cities. Second, only the customers of large-scale stores were included in the survey as respondents. Relatively large traditional markets are held every five days in local cities and there is competition between large-scale stores and traditional markets with regard to diversity and the price of goods. It could be expected that customers in large-scale stores and customers in traditional markets would hold different store images. In future studies, images of stores in large cities should be compared with the images of stores located in small local cities. In addition, customer behavior when buying goods in large-scale stores should be compared with their behavior when buying goods in traditional markets.

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The Relationship between Internet Search Volumes and Stock Price Changes: An Empirical Study on KOSDAQ Market (개별 기업에 대한 인터넷 검색량과 주가변동성의 관계: 국내 코스닥시장에서의 산업별 실증분석)

  • Jeon, Saemi;Chung, Yeojin;Lee, Dongyoup
    • Journal of Intelligence and Information Systems
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    • v.22 no.2
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    • pp.81-96
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    • 2016
  • As the internet has become widespread and easy to access everywhere, it is common for people to search information via online search engines such as Google and Naver in everyday life. Recent studies have used online search volume of specific keyword as a measure of the internet users' attention in order to predict disease outbreaks such as flu and cancer, an unemployment rate, and an index of a nation's economic condition, and etc. For stock traders, web search is also one of major information resources to obtain data about individual stock items. Therefore, search volume of a stock item can reflect the amount of investors' attention on it. The investor attention has been regarded as a crucial factor influencing on stock price but it has been measured by indirect proxies such as market capitalization, trading volume, advertising expense, and etc. It has been theoretically and empirically proved that an increase of investors' attention on a stock item brings temporary increase of the stock price and the price recovers in the long run. Recent development of internet environment enables to measure the investor attention directly by the internet search volume of individual stock item, which has been used to show the attention-induced price pressure. Previous studies focus mainly on Dow Jones and NASDAQ market in the United States. In this paper, we investigate the relationship between the individual investors' attention measured by the internet search volumes and stock price changes of individual stock items in the KOSDAQ market in Korea, where the proportion of the trades by individual investors are about 90% of the total. In addition, we examine the difference between industries in the influence of investors' attention on stock return. The internet search volume of stocks were gathered from "Naver Trend" service weekly between January 2007 and June 2015. The regression model with the error term with AR(1) covariance structure is used to analyze the data since the weekly prices in a stock item are systematically correlated. The market capitalization, trading volume, the increment of trading volume, and the month in which each trade occurs are included in the model as control variables. The fitted model shows that an abnormal increase of search volume of a stock item has a positive influence on the stock return and the amount of the influence varies among the industry. The stock items in IT software, construction, and distribution industries have shown to be more influenced by the abnormally large internet search volume than the average across the industries. On the other hand, the stock items in IT hardware, manufacturing, entertainment, finance, and communication industries are less influenced by the abnormal search volume than the average. In order to verify price pressure caused by investors' attention in KOSDAQ, the stock return of the current week is modelled using the abnormal search volume observed one to four weeks ahead. On average, the abnormally large increment of the search volume increased the stock return of the current week and one week later, and it decreased the stock return in two and three weeks later. There is no significant relationship with the stock return after 4 weeks. This relationship differs among the industries. An abnormal search volume brings particularly severe price reversal on the stocks in the IT software industry, which are often to be targets of irrational investments by individual investors. An abnormal search volume caused less severe price reversal on the stocks in the manufacturing and IT hardware industries than on average across the industries. The price reversal was not observed in the communication, finance, entertainment, and transportation industries, which are known to be influenced largely by macro-economic factors such as oil price and currency exchange rate. The result of this study can be utilized to construct an intelligent trading system based on the big data gathered from web search engines, social network services, and internet communities. Particularly, the difference of price reversal effect between industries may provide useful information to make a portfolio and build an investment strategy.

Domestic Disabled People's Use of Dental Service Institutes and Their Oral Health Related Quality of Life (재가 장애인의 구강진료기관 이용실태와 구강건강관련 삶의 질)

  • Lee, Hyun-Ok;Yang, Chun-Ho;Kim Jin;Kim, Young-Im
    • Journal of dental hygiene science
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    • v.9 no.5
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    • pp.593-600
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    • 2009
  • In this study, disabled people's life quality according to their use of dental healthcare services were examined, and the factors that influence their life quality were examined. The subjects in this study were 198 domestic disabled people in Jeollabuk-do, on whom a survey was conducted from May 1 to June 1, 2008. After the collected data were analyzed with SPSS WIN 12.0 program, the following findings were acquired: 1. 68.2% of the subjects had an experience of using dental service institutes. Over 80.0% of the physically disabled, the mentally handicapped, and the sensory-disturbance sufferers each used dental service institutes in their locations. Regarding the reason for visiting dental service institutes, 43.4% of the physically disabled visited for regular examination (the largest group for that reason), followed by the mentally handicapped with 37.9%. 43.5% of the sensory-disturbance sufferers visited for pain and fracture. 2. The subjects' life quality level relating to oral health was found to be an average 3.39 point score. There was a statistically significant difference in their life quality levels in terms of demographic features, such as age, religion, marriage/non-marriage, education, and subjective health status variables. Those experienced in using dental service institutes enjoyed higher levels of life quality (p=.011). And, with regard to disability characteristics, the degree of disability and the period of disability influenced the quality of life with a statistical significance. 3. Regarding variables influencing the life quality of subjects, in terms of general characteristic variables, subjective health status were influential variables, and in terms of characteristic variables relating to the use of dental clinics and disability, the experience of using dental service institutes influenced the quality of life. In conclusion, nationwide efforts to nurture separate dental personnels responsible for the disabled, to expand relevant facilities and to improve the health care insurance are required to promote the oral health of domestic disabled people's.

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A Study on Recognition and Practice of Teakyo by Pregnant Women (임부의 태교인식과 태교실천에 관한 조사연구)

  • Shin, Yong-Bun;Koh, Hyo-Jung
    • Women's Health Nursing
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    • v.6 no.1
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    • pp.142-152
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    • 2000
  • This study is a descriptive study to offer an actual basic data as Nursing intervention strategy of nurses before delivery in order that pregnant women in Korea may effectively practice Taekyo by examining the relation after apprehending level of recognition and practice of our pregnant women about Taekyo. This study collected questionnaires from 801 pregnant women who visited general hospitals in 10 areas(Seoul, Daejon, chunan, Daegu, Kummi, $Ky{\check{o}}ngju$, $P{\ddot{o}}hang$, Busan, $J{\ddot{o}}nju$, and $Y{\ddot{o}}nkwang$) for prenatal care through an outpatient obstetrics and gynecology from July 15 to August 30, 1999. This study used the tool of lee, Ki Young(1993) revised an complemented by investigator to measure recognition of Taekyo and the tool of Jang, Shun Buk and Park, Young Ju(1996) revised and complemented by investigator to measure practice of Taekyo. The Cronbach's alpha value of each tool was .88 in recognition of Taekyo, while the value was .90 in practice of Taekyo. For data analysis, this study used the descriptive and statistical analysis, Pearson correlation, t-test, ANOVA, Tukey's post hoc contrast, and Stepwise multiple regression in accordance with the purpose of this study with using SPSS Win 7.5 program. The results were as follows ; 1. The practice of Taekyo was low in comparison with recognition of Teakyo by showing average 4.28 points and standard deviation 0.48 at level of recognition of pregnant women about Taekyo on the basis of 5 points and showing to show average 2.81 points and standard deviation 0.36 at practice level on the basis of 4 points. 2. They showed the higher level of recognition on Taekyo at high educational background of pregnant woman(F=3.735, p=.005), Roman catholicism (F=4.570, p=.002), satisfied married life(F=5.448, p=.004), high monthly income(F=6.096, p=.000) and cases of hoping pregnancy(F=2.525, p=.012). 3. They showed the higher level of practice on Taekyo at high educational background of pregnant woman(F=2.883, P=.022), Roman catholicism(F=3.616, p=.032), satisfied married life(F=19.924, p=.000), good health condition(F=2.386, p=.017), cases of hoping pregnancy(F=0.677, p=.000), cases of planning pregnancy with husband(F=3.024, p=.001), cases of regular prenatal care before delivery(F=0.241, p=.005), cases of maternal breast feeding (F=9.132, p=.000), and the number of less children(F=2.763, p=.041). 4. In result of examining correlation between recognition and practice of Taekyo, they showed high level of practice on Taekyo under high level of recognition of pregnant women on Taekyo by showing the statistically significant correlation. 5. In result of examining the related factors that affect recognition and practice of Taekyo y the object, practice of Taekyo had 16.8 percents of explanatory range, purpose of practicing Taekyo 8.5 percents of explanatory range, and monthly income 1.9 percent of explanatory range as variables of affecting recognition of Taekyo. The total explanatory range was 27.2 percents, Recognition of Taekyo had 16.1 percents of explanatory ragne, time of starting Taekyo 3.2 percents, health condition 2.2 percents of explanatory range, condition of hoping pregnancy 1.1 percent of explanatory range, satisfaction of married life 0.8 percent of explanatory range, and religion 0.6 percent of explanatory range as variables of affecting practice of Taekyo. The total explanatory range was 24.0 percents.

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Comparison of Anterior Segment Features between Groups with or without Glaucoma in Pseudoexfoliation Syndrome (거짓비늘증후군에서 개방각녹내장 병합 유무에 따른 전안부 소견과 생체 계측치에 대한 비교)

  • Gu, Bon Hyeok;Choi, Sangkyung
    • Journal of The Korean Ophthalmological Society
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    • v.59 no.11
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    • pp.1049-1055
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    • 2018
  • Purpose: To investigate the factors associated with glaucoma in patients with pseudoexfoliation syndrome by comparing features of the anterior segments and ocular biometry according to the presence or absence of open-angle glaucoma in pseudoexfoliation syndrome. Methods: We analyzed 96 patients (115 eyes) diagnosed as having pseudoexfoliation syndrome in this study. The patients were divided into two groups of simple pseudoexfoliation syndrome (64 patients, 76 eyes) and pseudoexfoliation glaucoma (32 patients, 39 eyes). We compared the age, sex, underlying disease, location of pseudoexfoliative material, iris change, degree of nuclear cataract, pupil dilatation, corneal endothelial cell counts, central corneal thickness, anterior chamber depth, axial length, corneal curvature, and intraocular pressure (IOP). Results: There were no significant differences between the two groups in terms of age (p = 0.694), sex (p = 0.161), diabetes (p = 0.440), hypertension (p = 0.238), pseudoexfoliative material observed in anterior capsule (p = 0.700), pupillary margin (p = 0.210), iris depigmentation (p = 0.526), pupillary ruff loss (p = 0.708), degree of nuclear cataract (p = 0.617), pupil dilatation (p = 0.526), central corneal thickness (p = 0.097), anterior chamber depth (p = 0.283), axial length (p = 0.095), or horizontal and vertical corneal curvature (p = 0.066 and 0.306, respectively). In pseudoexfoliation glaucoma, significantly higher IOP (p = 0.026), a high frequency of membrane formation (p = 0.047), and decreased corneal endothelial cell counts (p = 0.048) were observed. Conclusions: Pseudoexfoliation syndrome with open-angle glaucoma was shown to be associated with high IOP, decreased corneal endothelial cell counts, and a high frequency of membrane formation. Therefore, when such changes are observed in pseudoexfoliation syndrome patients, a higher risk of open-angle glaucoma should be recognized, and careful attentionis required accordingly.

The Applicable Laws to International Intellectual Property License Contracts under the Rome I Regulation (국제 지식재산권 라이센스 계약 분쟁의 준거법 결정 원칙으로서 로마I 규정의 적용에 관한 연구)

  • Moon, Hwa-Kyung
    • Journal of Legislation Research
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    • no.44
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    • pp.487-538
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    • 2013
  • It is the most critical issue in recent international intellectual property licence disputes to decide the applicable laws to the license contracts. As Korea and the European Union(EU) reached free trade agreement(FTA), and the EU-Korea FTA entered into force on July 1, 2011, the FTA has boosted social, economic, cultural exchanges between the two. As a result of the increased transactions in those sectors, legal disputes are also expected to grow. This situation calls for extensive research and understanding of the choice of law principles applicable to international intellectual property license contracts in the EU. To decide the laws applicable to issues arising from international intellectual property license contracts disputes, the characterization of those issues is necessary for the purpose of applying private international law principles to them. In terms of characterization, intellectual property license contracts fall within contractual matters. In the EU, the primary rule of choice of law principles in contractual obligations is the Rome I Regulation. Because the choice of law rules, such as private international law principles, the Rome Convention(1980), and the Rome I Regulation, differ in the time of application, it is essential to clarify the time factor of related contracts. For example, the Rome I Regulation applies to contracts which were concluded as from December 17, 2009. Although party autonomy in international contracts disputes is generally allowed, if there is no choice of law agreement between the parties to the contracts, the objective test rule of private international law doctrine could be the best option. Following this doctrine, the Rome I Regulation Article 4, Paragraph 1 provides the governing law rules based on the types of contracts, but there is no room for intellectual property license contracts. After all, as the rule for governing law of those contracts, the Rome I Regulation Article 4, Paragraph 2 should be applied and if there are countries which are more closely connected to the contracts under the Rome I Regulation Article 4, Paragraph 3, the laws of those countries become the governing laws of the contracts. Nevertheless, if it is not possible to decide the applicable laws to the license contracts, the Rome I Regulation Article 4, Paragraph 4 should be applied in the last resort and the laws of the countries which are the most closely connected to the contracts govern the license contracts. Therefore, this research on the laws applicable to intellectual property license contracts under the Rome I Regulation suggests more systematic and effective solutions for future disputes in which Korea and the EU countries play the significant role as the connecting factors in the conflict of laws rules. Moreover, it helps to establish comprehensive and theoretical understanding of applying the Korean Private International Law to multifarious choice-of-law cases.

The effects of housing poverty on adolescents' subjective well-being (주거빈곤기간이 청소년의 주관적 행복감에 미치는 영향)

  • Lim, Se Hee;Kim, SunSuk
    • Journal of the Korean Society of Child Welfare
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    • no.56
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    • pp.133-164
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    • 2016
  • This study investigated the effect of housing poverty in childhood on adolescents' subjective well-being. Specifically, this study examined whether the major factors that have been known to affect adolescents' well-being (i.e., family relationships, peer relationships, school adjustment etc.) mediated the relationship between housing poverty and adolescents' well-being. And then this study aimed to present an empirical evidence for establishing policies against housing poverty in order to enhance adolescent's subjective happiness. Data were derived from the $1^{st}$, $4^{th}$, and $7^{th}$ surveys of the Korea Welfare Panel Study(KOWEPS), and the sample included. 512 high school children in the $7^{th}$ survey. This study utilized structural equation modeling. Housing poverty was measured by the sub-minimum standard housing condition and the household's burden of housing expenditure. Family relationship, as a mediator, was measured by parental involvement in education, parental monitoring, and family conflicts. Another mediator, school adjustment was measured by school environment and school bonding, and the last mediator, peer relationship was measured by friend attachment and peer attachment. The results showed that housing poverty had significant negative effects on the adolescents' subjective well-being. The sub-minimum standard housing condition with inadequate size and facilities negatively affected adolescents' relationships with family directly and subjective well-being indirectly. In addition, the negative family relationships due to the sub-minimum standard housing condition negatively affected adolescents' subjective well-being through school adjustment and peer relationships. The greater the proportion of income a household spends on housing expenditure, the less likely for adolescents to report positive well-being. The sub-minimum standard housing condition had indirect effects through family relationships, whereas the household's housing expenditure directly affected adolescents' subjective well-being. This study suggested the necessity of interventions to alleviate housing poverty for adolescents' families and lays the groundwork for housing poverty policies in Korea.

A Study on Perception Change in Bicycle users' Outdoor Activity by Particulate Matter: Based on the Social Network Analysis (미세먼지로 인한 자전거 이용객의 야외활동 인식변화에 관한 연구: 사회네트워크분석을 중심으로)

  • Kim, Bomi;Lee, Dong Kun
    • Journal of Environmental Impact Assessment
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    • v.28 no.5
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    • pp.440-456
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    • 2019
  • The controversy of the risk perception related to particulate matters becomes significant. Therefore, in order to understand the nature of the particulate matters, we gathered articles and comments in on-line community related to bicycling which is affected by exposure of the particulate matters. As a result, firstly, the government - led particulate matter policy was strengthened and segmented every period, butthe risk perception related to particulate matters in the bicycle community has become active and serious. Second, as a result of analyzing the perception change of outdoor activities related to particulate matters, bicycle users in community showed a tendency of outdoor activity depending on the degree of particulate matters ratherthan the weather. In addition, the level of the risk perception related to particulate matters has been moved from fears of serious threat in daily life and health, combined with the disregard of domestic particulate matter levels or mask performance. Ultimately, these risk perception related to particulate matters have led some of the bicycling that were mainly enjoyed outdoors to the indoor space. However, in comparison with outdoor bicycling enjoyed by various factors such as scenery, people, and weather, the monotonous indoor bicycling was converted into another type of indoor exercise such as fitness and yoga. In summary, it was derived from mistrust of excessive information or policy provided by the government or local governments. It is considered that environmental policy should be implemented after discussion of risk communication that can reduce the gap between public anxiety and concern so as to cope with the risk perception related to particulate matters. Therefore,this study should be provided as an academic basis for the effective communication direction when decision makers establish the policy related to particulate matters.

Effect of Low-dose Aspirin on Implantation and Pregnancy Rates in Patients Undergoing Frozen-thawed Embryo Transfer (동결보존 배아 이식에서 저 용량 아스피린 투여가 임신율과 착상율에 미치는 영향에 관한 연구)

  • Kim, Min Ji;Lee, Hyun Jung;Yu, Young;Seo, Back Kyung;Cha, Sun Hwa;Kim, Hae Suk;Song, In Ok;Byun, Hye Kyung;Koong, Mi Kyoung;Kang, Inn Soo;Yang, Kwang Moon
    • Clinical and Experimental Reproductive Medicine
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    • v.32 no.3
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    • pp.243-251
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    • 2005
  • Objective: Low-dose aspirin have been proposed to improving endometrial receptivity and pregnancy rate in COH-IVF by increasing endometrial perfusion. However, the effect of low-dose aspirin in COH-IVF could be negligible because there have been large quantity of other important factors responsible for changing endometrial perfusion accompanied by COH procedure. In contrast, in frozen-thawed embryo transfer cycles which were not accompanied by COH procedure, the effects of low-dose aspirin in endometrial blood flow seems to be more certain than in COH-IVF cycles. In this study, we analyzed the effect of low-dose aspirin treatment on implantation and pregnancy rates in patients undergoing frozen-thawed embryo transfer Methods: From January 2003 to December 2003, total 264 cycles from 264 patients who attended infertility clinic at Samsung Cheil Hospital were enrolled in this study. All cases included in this study, embryos were frozen and thawed at the pronuclear stage and three days after incubation, at least 2 or more good quality embryos were transferred into uterus. In study group, low dose aspirin (100 mg/day) was administrated from the first or second date of menstrual day to 9 days after embryo transfer. On the other hand, control group did not take any medicine except estradiol valerate for endometrial priming. Several variables including implantation and pregnancy rates were compared in both groups. After then, each groups were stratified by endometrial thickness checked at embryo transfer (ET) day such as (28 mm versus <8 mm) and same variables above described were compared between study and control groups. Results: The mean age, infertility duration, endometrial thickness at embryo transfer day and mean number of transferred embryo were not significantly different in both groups. Also, implantation rates (study group: 15.8%, control group: 20.5%) and pregnancy rate (study group: 45.1%, control group: 43.5%) were not significantly different between two groups. (p>0.05) After we analyzed same variables stratified by endometrial thickness checked at embryo transfer day, we could not found any significant difference between study and control groups. Conclusions: Low-dose aspirin treatment seems to have no advantage of improving implantation and pregnancy rates in patients undergoing frozen-thawed embryo transfer.

Recent research activities on hybrid rocket in Japan

  • Harunori, Nagata
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2011.04a
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    • pp.1-2
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    • 2011
  • Hybrid rockets have lately attracted attention as a strong candidate of small, low cost, safe and reliable launch vehicles. A significant topic is that the first commercially sponsored space ship, SpaceShipOne vehicle chose a hybrid rocket. The main factors for the choice were safety of operation, system cost, quick turnaround, and thrust termination. In Japan, five universities including Hokkaido University and three private companies organized "Hybrid Rocket Research Group" from 1998 to 2002. Their main purpose was to downsize the cost and scale of rocket experiments. In 2002, UNISEC (University Space Engineering Consortium) and HASTIC (Hokkaido Aerospace Science and Technology Incubation Center) took over the educational and R&D rocket activities respectively and the research group dissolved. In 2008, JAXA/ISAS and eleven universities formed "Hybrid Rocket Research Working Group" as a subcommittee of the Steering Committee for Space Engineering in ISAS. Their goal is to demonstrate technical feasibility of lowcost and high frequency launches of nano/micro satellites into sun-synchronous orbits. Hybrid rockets use a combination of solid and liquid propellants. Usually the fuel is in a solid phase. A serious problem of hybrid rockets is the low regression rate of the solid fuel. In single port hybrids the low regression rate below 1 mm/s causes large L/D exceeding a hundred and small fuel loading ratio falling below 0.3. Multi-port hybrids are a typical solution to solve this problem. However, this solution is not the mainstream in Japan. Another approach is to use high regression rate fuels. For example, a fuel regression rate of 4 mm/s decreases L/D to around 10 and increases the loading ratio to around 0.75. Liquefying fuels such as paraffins are strong candidates for high regression fuels and subject of active research in Japan too. Nakagawa et al. in Tokai University employed EVA (Ethylene Vinyl Acetate) to modify viscosity of paraffin based fuels and investigated the effect of viscosity on regression rates. Wada et al. in Akita University employed LTP (Low melting ThermoPlastic) as another candidate of liquefying fuels and demonstrated high regression rates comparable to paraffin fuels. Hori et al. in JAXA/ISAS employed glycidylazide-poly(ethylene glycol) (GAP-PEG) copolymers as high regression rate fuels and modified the combustion characteristics by changing the PEG mixing ratio. Regression rate improvement by changing internal ballistics is another stream of research. The author proposed a new fuel configuration named "CAMUI" in 1998. CAMUI comes from an abbreviation of "cascaded multistage impinging-jet" meaning the distinctive flow field. A CAMUI type fuel grain consists of several cylindrical fuel blocks with two ports in axial direction. The port alignment shifts 90 degrees with each other to make jets out of ports impinge on the upstream end face of the downstream fuel block, resulting in intense heat transfer to the fuel. Yuasa et al. in Tokyo Metropolitan University employed swirling injection method and improved regression rates more than three times higher. However, regression rate distribution along the axis is not uniform due to the decay of the swirl strength. Aso et al. in Kyushu University employed multi-swirl injection to solve this problem. Combinations of swirling injection and paraffin based fuel have been tried and some results show very high regression rates exceeding ten times of conventional one. High fuel regression rates by new fuel, new internal ballistics, or combination of them require faster fuel-oxidizer mixing to maintain combustion efficiency. Nakagawa et al. succeeded to improve combustion efficiency of a paraffin-based fuel from 77% to 96% by a baffle plate. Another effective approach some researchers are trying is to use an aft-chamber to increase residence time. Better understanding of the new flow fields is necessary to reveal basic mechanisms of regression enhancement. Yuasa et al. visualized the combustion field in a swirling injection type motor. Nakagawa et al. observed boundary layer combustion of wax-based fuels. To understand detailed flow structures in swirling flow type hybrids, Sawada et al. (Tohoku Univ.), Teramoto et al. (Univ. of Tokyo), Shimada et al. (ISAS), and Tsuboi et al. (Kyushu Inst. Tech.) are trying to simulate the flow field numerically. Main challenges are turbulent reaction, stiffness due to low Mach number flow, fuel regression model, and other non-steady phenomena. Oshima et al. in Hokkaido University simulated CAMUI type flow fields and discussed correspondence relation between regression distribution of a burning surface and the vortex structure over the surface.

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