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The significance and structural improvement of burial mound in Geonwonneung and Heonneung in the early Joseon Dynasty - Focusing on the Byeongpungsadaeseok and Nanganseok - (조선초 건원릉과 헌릉의 봉릉 구조개선과 의의 - 병풍사대석과 난간석을 중심으로 -)

  • SHIN Jihye
    • Korean Journal of Heritage: History & Science
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    • v.55 no.4
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    • pp.118-135
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    • 2022
  • The primary purpose of this study is to estimate the structure of Byeongpungsadaseok (屛風莎臺石) and Nanganseok (欄干石) in Geonwonneung (建元陵) and Heonneung (獻陵), which were built in the early of 15th century, based on the Annals of King Sejong. In addition, the ultimate purpose of this study is to reveal structural changes and their significance by comparing the differences with the contents of the dismantlement survey. Geonwonneung, Jereung(齊陵), and Heonneung were repaired at the same time in 1442, and the structural changes were the similar. The purpose of the repair in 1442 was to prevent water from flowing into the underground palace with smooth drainage. As a result of estimating the structure of Geonwonneung and Heonneung according to the records of the Annals of King Sejong, it was created in a very similar form to the Hyeonneung and Jeongneung of Goryeo. And it was clearly recognized that the Royal Tomb of Goryeo was followed. However, as the structure was improved in 1442, the unique characteristics of the Royal Tomb of the Joseon Dynasty were formed. First is the appearance of the Bokbuhyeong lime (覆釜形石灰, which is a convex roof on the Byeongpungsadaseok that serves to prevent rainwater from penetrating into the burial mound. It also plays a role in connecting and fixing the Manseok (滿石) and the Inseok (引石), which are the upper structures of the Sadaseok (莎臺石). Second, the Bakseok (薄石) between the nanganseok and the sadaseok has been transformed into the Sangseok (裳石) with a slope. This plays a role in protecting the inner stone chamber by expanding the length of the bakseok, which forms an overall slope, like the eaves of the roof. After both of these features were first attempted in 1442, they were applied to all Royal Tombs of the Joseon Dynasty and became unique features of these Royal Tombs.

How Do Students Use Conceptual Understanding in the Design of Sensemaking?: Considering Epistemic Criteria for the Generation of Questions and Design of Investigation Processes (중학생의 센스메이킹 설계에서 개념적 이해는 어떻게 활용되는가? -질문 고안과 조사 과정 설계에서 논의된 인식적 준거를 중심으로-)

  • Heesoo Ha
    • Journal of The Korean Association For Science Education
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    • v.43 no.6
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    • pp.495-507
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    • 2023
  • Teachers often encounter challenges in supporting students with question generation and the development of investigation plans in sensemaking activities. A primary challenge stems from the ambiguity surrounding how students apply their conceptual understandings in this process. This study aims to explore how students apply their conceptual understandings to generate questions and design investigation processes in a sensemaking activity. Two types of student group activities were identified and examined for comparison: One focused on designing a process to achieve the goal of sensemaking, and the other focused on following the step-by-step scientific inquiry procedures. The design of investigation process in each group was concretized with epistemic criteria used for evaluating the designs. The students' use of conceptual understandings in discussions around each was then examined. The findings reveal three epistemic criteria employed in generating questions and designing investigation processes. First, the students examined the interestingness of natural phenomena, using their conceptual understandings of the structure and function of entities within natural phenomena to identify a target phenomenon. This process involved verifying their existing knowledge to determine the need for new understanding. The second criterion was the feasibility of investigating specific variables with the given resources. Here, the students relied on their conceptual understandings of the structure and function of entities corresponding to each variable to assess whether each variable could be investigated. The third epistemic criterion involved examining whether the factors of target phenomena expressed in everyday terms could be translated into observable variables capable of explaining the phenomena. Conceptual understandings related to the function of entities were used to translate everyday expressions into observable variables and vice versa. The students' conceptual understanding of a comprehensive mechanism was used to connect the elements of the phenomenon and use the elements as potential factors to explain the target phenomenon. In the case where the students focused on carrying out step-by-step procedures, data collection feasibility was the sole epistemic criterion guiding the design. This study contributes to elucidating how the process of a sensemaking activity can be developed in the science classroom and developing conceptual supports for designing sensemaking activities that align with students' perspectives.

Failure experience and aspirations for the future: Indigenous psychological analysis of Korean adolescents and their parents (청소년과 부모의 실패와 미래성취 의식을 통해 본 한국인의 성취관련 토착심리)

  • Young-Shin Park;Uichol Kim;Sooyeun Tak
    • Korean Journal of Culture and Social Issue
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    • v.11 no.2
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    • pp.73-108
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    • 2005
  • This study examines the failure experience and aspirations for future among Korean adolescents and their parents using indigenous psychological analysis. The first part of this paper reviews the achievement literature that has used indigenous psychological analysis. The second part of this paper provides an empirical analysis of 482 students (primary=117, middle school=88, high school=72, and university=205) and 507 parents of the adolescents (fathers= 236, mothers=271). The open-ended questionnaire developed by Park and Kim (1999) was adopted for the study that asked the respondents to list the most painful experience, the person that was the most responsible for the failure, and the most important reason for the failure. The section on aspirations for the future asked the respondents to list the achievement that they would most likely to succeed, the person that they need assistance from, the type of support they need from the person, and the most important factor that would lead to them to success. The results indicate that for students the most painful failure was related to academic failure and for adults, it was related to family life. The person that was most responsible for the failure was reported by both samples be themselves. As for the most important factor that influenced their failure was a lack of self-regulation, such as a lack of effort and persistence. For the aspiration for future, students listed academic and occupational success and for adults listed harmonious family life as the most important. For social support, the adolescents listed their parents and adults listed their spouse as the person that they need assistance from. As for type of support, they listed emotional support to be the most important. As for the most important factor that would contribute to their success, majority of students and adults listed self-regulation. Based on these results and previous indigenous studies indicate, the following four conclusions could be drawn: (1) the emphasis of self-regulation as the most important reason for their past achievement, the future success and the lack of self-regulation for their failure; (2) the importance of receiving emotional support from family members; (3) the importance of educational aspiration and achievement for providing the basis of economic development; and 4) the importance goal of achieving harmonious family life.

Comparison of Spodoptera frugiperda Control Effects for Corn According to the Control Thresholds and Chemical Spraying Methods (열대거세미나방에 대한 옥수수의 요방제 수준 및 약제 살포방법에 따른 방제 효과 비교)

  • You Kyoung Lee;Hyun Ju Kim;Nak Jung Choi;Bo Yoon Seo;June Yeol Choi
    • Korean Journal of Agricultural and Forest Meteorology
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    • v.25 no.3
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    • pp.142-150
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    • 2023
  • As global warming continues, the time of invasion of Spodoptera frugiperda has been advanced and the inflow rate has been increasing, leading to great increases in damage to crops. In this study, in order to minimize crop damage caused by S. frugiperda, the control period was set for corn fields through control thresholds, and the control effects according to the chemical spraying methods were investigated in forage corn filed. Even under the condition of 4% injury level during the corn silking stage, the damage rate of ear was 70%, showing an aspect of extensive damage. The economic injury level of S. frugiperda second instar larvae was shown to be 0.7 larvae per stalk, and the control threshold level was shown to be 0.6 larvae. The income was calculated by applying the corn wholesale unit price, and according to the result, even under the condition of injury level of 4%, there was a loss of KRW 895,221/10a, and the higher the injury level, the greater the decrease in income. To control S. frugiperda, the insecticidal effects of 10 single formulations registered for S. frugiperda were tested, and according to the results, four types(emamectin benzoate, chlorantraniliprole, indoxacarb, and spinetoram) showed high insecticidal activity not lower than 93.3%, and three types (chloran- traniliprole, spinetoram, and indoxacarb) were considered to be effective in controlling S. frugiperda as they showed high residual effects through insecticidal effect persistence tests. Therefore, conventional control and aerial control were conducted twice at 7-day intervals with indoxacarb SC and chlorantraniliprol WP, which show high activity against S. frugiperda, respectively, prior to the silking of forage corn. As a result, conventional control showed higher control values, 46.3%p in the case of indoxacarb SC and 21.7%p in the case of chlorantraniliprol WP, than aerial control through the primary control. In the secondary control too, higher control values of 26.7%p in the case of indoxacarb SC and 40.4%p in the case of chlorantraniliprol WP were found in conventional control than in aerial control. Therefore, it is considered necessary to prepare measures to improve the control effects in the recent situation where alternative methods for manpower control are widely used.

Survey of elementary school teachers' perceptions of the 2022 revised mathematics curriculum (2022 개정 수학과 교육과정에 대한 초등학교 교사들의 인식 조사)

  • Kwon, Jeom-rae
    • Education of Primary School Mathematics
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    • v.27 no.2
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    • pp.111-137
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    • 2024
  • The purpose of this study is to identify the expected difficulties and necessary support when applying the 2022 revised mathematics curriculum to elementary schools, and to support the establishment of the field. To this end, we explored the major changes in the 2022 revised mathematics curriculum, and based on this, we conducted a survey of elementary school teachers to identify the expected difficulties and necessary support when applying it in the field. In particular, when analyzing the results, we also examined whether there were any differences in the expected difficulties and necessary support depending on the size of the school where it is located and the teaching experience of the teacher. The research results are as follows. First, the proportion of teachers who expect difficulties in applying the 2022 revised mathematics curriculum was mostly below 50%, but the proportion of teachers who demand support was much higher, at around 80%. Second, the difficulty of elementary school teachers in applying the 2022 revised mathematics curriculum was found to be the greatest in evaluation. Third, in relation to the use of edutech, teachers in elementary schools are also expected to have difficulties in teaching and learning methods to foster students' digital literacy, assessment using teaching materials or engineering tools, and assessment in online environments. Fourth, the difficulty of elementary school teachers in applying the 2022 revised mathematics curriculum was also significant in relation to mathematics subject competencies. Fifth, it was found that there is also difficulty in understanding the major changes of the achievement standards, including the addition, deletion, and adjustment of the achievement standards, and the impact on the learning of other achievement standards. Finally, the responses of elementary school teachers to the expected difficulties and necessary support in applying the 2022 revised mathematics curriculum did not differ depending on the size of the school where it is located, but statistically significant differences were found in a number of items depending on the teaching experience of the teacher. Based on these research results, we hope that various support will be provided for the 2022 revised mathematics curriculum, which will be applied annually from 2024.

Incidence of Dental Discoloration After Tetracycline Exposure in Korean Children: A Nationwide Population-Based Study

  • Ji Young Lee;Eun Hwa Kim;Myeongjee Lee;Jehee Shin;Sung Min Lim;Jee Yeon Baek;MinYoung Kim;Jong Gyun Ahn;Chung-Min Kang;Inkyung Jung;Ji-Man Kang
    • Pediatric Infection and Vaccine
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    • v.31 no.1
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    • pp.25-36
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    • 2024
  • Purpose: Tetracycline is not recommended for children under 12 by guideline due to the risk of tooth discoloration. We aimed to assess the incidence of dental discoloration in Korean children prescribed tetracyclines and investigate whether its risk was greater in tetracycline-exposed children than in the general population. Methods: This population-based cohort study using the Health Insurance Review and Assessment service database included children aged 0-12 years exposed to tetracyclines for at least 1 day between January 2008 and December 2020. The primary outcome was the incidence rate of dental discoloration ≥6 months after prescription, and the standardized incidence ratio (SIR) was evaluated as secondary outcome. Results: 56,990 children were included-1,735 and 55,255 aged <8 and 8-12 years, respectively. 61% children were prescribed tetracycline for <14 days with mostly second-generation tetracyclines, doxycycline (61%) and minocycline (35%). The 5- and 10-year cumulative incidence rates of dental discoloration were 4.1% (95% confidence interval [CI], 3.0-5.7%) and 5.7% (95% CI, 4.1% to 7.8%), respectively, in the 0-7 years age group and 0.8% (95% CI, 0.7% to 0.9%) and 1.3 (95% CI, 1.1% to 1.4%), respectively, in the 8-12 years age group. Tetracycline exposure did not increase such risk compared to that in the general population (SIR, 1.08; 95% CI, 0.69 to 1.60). Conclusions: The incidence of dental discoloration was lower than previously suggested. Relieving the age restriction for prescribing tetracyclines may be considered.

Study on the Effects of Shop Choice Properties on Brand Attitudes: Focus on Six Major Coffee Shop Brands (점포선택속성이 브랜드 태도에 미치는 영향에 관한 연구: 6개 메이저 브랜드 커피전문점을 중심으로)

  • Yi, Weon-Ho;Kim, Su-Ok;Lee, Sang-Youn;Youn, Myoung-Kil
    • Journal of Distribution Science
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    • v.10 no.3
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    • pp.51-61
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    • 2012
  • This study seeks to understand how the choice of a coffee shop is related to a customer's loyalty and which characteristics of a shop influence this choice. It considers large-sized coffee shops brands whose market scale has gradually grown. The users' choice of shop is determined by price, employee service, shop location, and shop atmosphere. The study investigated the effects of these four properties on the brand attitudes of coffee shops. The effects were found to vary depending on users' characteristics. The properties with the largest influence were shop atmosphere and shop location Therefore, the purpose of the study was to examine the properties that could help coffee shops get loyal customers, and the choice properties that could satisfy consumers' desires The study examined consumers' perceptions of shop properties at selection of coffee shop and the difference between perceptual difference and coffee brand in order to investigate customers' desires and needs and to suggest ways that could supply products and service. The research methodology consisted of two parts: normative and empirical research, which includes empirical analysis and statistical analysis. In this study, a statistical analysis of the empirical research was carried out. The study theoretically confirmed the shop choice properties by reviewing previous studies and performed an empirical analysis including cross tabulation based on secondary material. The findings were as follows: First, coffee shop choice properties varied by gender. Price advantage influenced the choice of both men and women; men preferred nearer coffee shops where they could buy coffee easily and more conveniently than women did. The atmosphere of the coffee shop had the greatest influence on both men and women, and shop atmosphere was thought to be the most important for age analysis. In the past, customers selected coffee shops solely to drink coffee. Now, they select the coffee shop according to its interior, menu variety, and atmosphere owing to improved quality and service of coffee shop brands. Second, the prices of the brands did not vary much because the coffee shops were similarly priced. The service was thought to be more important and to elevate service quality so that price and employee service and other properties did not have a great influence on shop choice. However, those working in the farming, forestry, fishery, and livestock industries were more concerned with the price than the shop atmosphere. College and graduate school students were also affected by inexpensive price. Third, shop choice properties varied depending on income. The shop location and shop atmosphere had a greater influence on shop choice. The customers in an income bracket of less than 2 million won selected low-price coffee shops more than those earning 6 million won or more. Therefore, price advantage had no relation with difference in income. The higher income group was not affected by employee service. Fourth, shop choice properties varied depending on place. For instance, customers at Ulsan were the most affected by the price, and the ones at Busan were the least affected. The shop location had the greatest influence among all of the properties. Among the places surveyed, Gwangju had the least influence. The alternate use of space in a coffee shop was thought to be important in all the cities under consideration. The customers at Ulsan were not affected by employee service, and they selected coffee shops according to quality and preference of shop atmosphere. Lastly, the price factor was found to be a little higher than other factors when customers frequently selected brands according to shop properties. Customers at Gwangju reacted to discounts more than those in other cities did, and the former gave less priority to the quality and taste of coffee. Brand preference varied depending on coffee shop location. Customers at Busan selected brands according to the coffee shop location, and those at Ulsan were not influenced by employee kindness and specialty. The implications of this study are that franchise coffee shop businesses should focus on customers rather than aggressive marketing strategies that increase the number of coffee shops. Thus, they should create an environment with a good atmosphere and set up coffee shops in places that customers have good access to. This study has some limitations. First, the respondents were concentrated in metropolitan areas. Secondary data showed that the number of respondents at Seoul was much more than that at Gyeonggi-do. Furthermore, the number of respondents at Gyeonggi-do was much more than those at the six major cities in the nation. Thus, the regional sample was not representative enough of the population. Second, respondents' ratio was used as a measurement scale to test the perception of shop choice properties and brand preference. The difficulties arose when examining the relation between these properties and brand preference, as well as when understanding the difference between groups. Therefore, future research should seek to address some of the shortcomings of this study: If the coffee shops are being expanded to local areas, then a questionnaire survey of consumers at small cities in local areas shall be conducted to collect primary material. In particular, variables of the questionnaire survey shall be measured using Likert scales in order to include perception on shop choice properties, brand preference, and repurchase. Therefore, correlation analysis, multi-regression, and ANOVA shall be used for empirical analysis and to investigate consumers' attitudes and behavior in detail.

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A Store Recommendation Procedure in Ubiquitous Market for User Privacy (U-마켓에서의 사용자 정보보호를 위한 매장 추천방법)

  • Kim, Jae-Kyeong;Chae, Kyung-Hee;Gu, Ja-Chul
    • Asia pacific journal of information systems
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    • v.18 no.3
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    • pp.123-145
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    • 2008
  • Recently, as the information communication technology develops, the discussion regarding the ubiquitous environment is occurring in diverse perspectives. Ubiquitous environment is an environment that could transfer data through networks regardless of the physical space, virtual space, time or location. In order to realize the ubiquitous environment, the Pervasive Sensing technology that enables the recognition of users' data without the border between physical and virtual space is required. In addition, the latest and diversified technologies such as Context-Awareness technology are necessary to construct the context around the user by sharing the data accessed through the Pervasive Sensing technology and linkage technology that is to prevent information loss through the wired, wireless networking and database. Especially, Pervasive Sensing technology is taken as an essential technology that enables user oriented services by recognizing the needs of the users even before the users inquire. There are lots of characteristics of ubiquitous environment through the technologies mentioned above such as ubiquity, abundance of data, mutuality, high information density, individualization and customization. Among them, information density directs the accessible amount and quality of the information and it is stored in bulk with ensured quality through Pervasive Sensing technology. Using this, in the companies, the personalized contents(or information) providing became possible for a target customer. Most of all, there are an increasing number of researches with respect to recommender systems that provide what customers need even when the customers do not explicitly ask something for their needs. Recommender systems are well renowned for its affirmative effect that enlarges the selling opportunities and reduces the searching cost of customers since it finds and provides information according to the customers' traits and preference in advance, in a commerce environment. Recommender systems have proved its usability through several methodologies and experiments conducted upon many different fields from the mid-1990s. Most of the researches related with the recommender systems until now take the products or information of internet or mobile context as its object, but there is not enough research concerned with recommending adequate store to customers in a ubiquitous environment. It is possible to track customers' behaviors in a ubiquitous environment, the same way it is implemented in an online market space even when customers are purchasing in an offline marketplace. Unlike existing internet space, in ubiquitous environment, the interest toward the stores is increasing that provides information according to the traffic line of the customers. In other words, the same product can be purchased in several different stores and the preferred store can be different from the customers by personal preference such as traffic line between stores, location, atmosphere, quality, and price. Krulwich(1997) has developed Lifestyle Finder which recommends a product and a store by using the demographical information and purchasing information generated in the internet commerce. Also, Fano(1998) has created a Shopper's Eye which is an information proving system. The information regarding the closest store from the customers' present location is shown when the customer has sent a to-buy list, Sadeh(2003) developed MyCampus that recommends appropriate information and a store in accordance with the schedule saved in a customers' mobile. Moreover, Keegan and O'Hare(2004) came up with EasiShop that provides the suitable tore information including price, after service, and accessibility after analyzing the to-buy list and the current location of customers. However, Krulwich(1997) does not indicate the characteristics of physical space based on the online commerce context and Keegan and O'Hare(2004) only provides information about store related to a product, while Fano(1998) does not fully consider the relationship between the preference toward the stores and the store itself. The most recent research by Sedah(2003), experimented on campus by suggesting recommender systems that reflect situation and preference information besides the characteristics of the physical space. Yet, there is a potential problem since the researches are based on location and preference information of customers which is connected to the invasion of privacy. The primary beginning point of controversy is an invasion of privacy and individual information in a ubiquitous environment according to researches conducted by Al-Muhtadi(2002), Beresford and Stajano(2003), and Ren(2006). Additionally, individuals want to be left anonymous to protect their own personal information, mentioned in Srivastava(2000). Therefore, in this paper, we suggest a methodology to recommend stores in U-market on the basis of ubiquitous environment not using personal information in order to protect individual information and privacy. The main idea behind our suggested methodology is based on Feature Matrices model (FM model, Shahabi and Banaei-Kashani, 2003) that uses clusters of customers' similar transaction data, which is similar to the Collaborative Filtering. However unlike Collaborative Filtering, this methodology overcomes the problems of personal information and privacy since it is not aware of the customer, exactly who they are, The methodology is compared with single trait model(vector model) such as visitor logs, while looking at the actual improvements of the recommendation when the context information is used. It is not easy to find real U-market data, so we experimented with factual data from a real department store with context information. The recommendation procedure of U-market proposed in this paper is divided into four major phases. First phase is collecting and preprocessing data for analysis of shopping patterns of customers. The traits of shopping patterns are expressed as feature matrices of N dimension. On second phase, the similar shopping patterns are grouped into clusters and the representative pattern of each cluster is derived. The distance between shopping patterns is calculated by Projected Pure Euclidean Distance (Shahabi and Banaei-Kashani, 2003). Third phase finds a representative pattern that is similar to a target customer, and at the same time, the shopping information of the customer is traced and saved dynamically. Fourth, the next store is recommended based on the physical distance between stores of representative patterns and the present location of target customer. In this research, we have evaluated the accuracy of recommendation method based on a factual data derived from a department store. There are technological difficulties of tracking on a real-time basis so we extracted purchasing related information and we added on context information on each transaction. As a result, recommendation based on FM model that applies purchasing and context information is more stable and accurate compared to that of vector model. Additionally, we could find more precise recommendation result as more shopping information is accumulated. Realistically, because of the limitation of ubiquitous environment realization, we were not able to reflect on all different kinds of context but more explicit analysis is expected to be attainable in the future after practical system is embodied.

Risk Factor Analysis and Surgical Indications for Pulmonary Artery Banding (폐동맥 밴딩의 위험인자 분석과 수술적응중)

  • Lee Jeong Ryul;Choi Chang Hyu;Min Sun Kyung;Kim Woong Han;Kim Yong Jin;Rho Joon Ryang;Bae Eun Jung;Noh Chung I1;Yun Yong Soo
    • Journal of Chest Surgery
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    • v.38 no.8 s.253
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    • pp.538-544
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    • 2005
  • Background: Pulmonary artery banding (PAB) is an initial palliative procedure for a diverse group of patients with congenital cardiac anomalies and unrestricted pulmonary blood flow. We proved the usefulness of PAB through retrospective investigation of the surgical indication and risk analysis retrospectively. Material and Method: One hundred and fifty four consecutive patients (99 males and 55 females) who underwent PAB between January 1986 and December 2003 were included. We analysed the risk factors for early mortality and actuarial survival rate. Mean age was $2.5\pm12.8\;(0.2\sim92.7)$ months and mean weight was $4.5\pm2.7\;(0.9\sim18.0)\;kg$. Preoperative diagnosis included functional single ventricle $(88,\;57.1\%)$, double outlet right ventricle $(22,\;14.2\%)$, transposition of the great arteries $(26,\;16.8\%)$, and atrioventricular septal defect $(11,\;7.1\%)$. Coarctation of the aorta or interrupted aortic arch $(32,\;20.7\%)$, subaortic stenosis $(13,\;8.4\%)$ and total anomalous pulmonary venous connection $(13,\;8.4\%)$ were associated. Result: The overall early mortality was $22.1\%\;(34\;of\;154)$, The recent series from 1996 include patients with lower age $(3.8\pm15.9\;vs.\;1.5\pm12.7,\;p=0.04)$ and lower body weight $(4.8\pm3.1\;vs.\;4.0\pm2.7,\;p=0.02)$. The early mortality was lower in the recent group $(17.5\%;\;16/75)$ than the earlier group $(28.5\%;\;18/45)$. Aortic arch anomaly (p=0.004), subaortic stenosis (p=0.004), operation for subaortic stenosis (p=0.007), and cardiopulmonary bypass (p=0.007) were proven to be risk factors for early death in univariate analysis, while time of surgery (<1996) (p=0.026) was the only significant risk factor in multivariate analysis. The mean time interval from PAB to the second-stage operation was $12.8\pm10.9$ months. Among 96 patients who survived PAB, 40 patients completed Fontan operation, 21 patients underwent bidirectional cavopulmonary shunt, and 35 patients underwent biventricular repair including 25 arterial switch operations. Median follow-up was $40.1\pm48.9$ months. Overall survival rates at 1 year, 5 years and 10 years were $81.2\%\;65.0\%,\;and\;63.5\%$ respectively. Conclusion: Although it improved in recent series, early mortality was still high despite the advances in perioperative management. As for conventional indications, early primary repair may be more beneficial. However, PA banding still has a role in the initial palliative step in selective groups.

The Hardness Water Production By RO/NF/ED Linking Process From Deep Seawater (RO/NF/ED 연계 공정에 의한 고경도 담수 제조)

  • Moon, Deok-Soo;Kim, Kwang Soo;Gi, Ho;Choi, Mi Yeon;Jung, Hyun Ji;Kim, Hyun Ju
    • Journal of the Korean Society for Marine Environment & Energy
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    • v.16 no.4
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    • pp.227-238
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    • 2013
  • The purpose of this study is to develop a process technology to produce high hardness drinking water which meet drinking water standard, remaining useful minerals like magnesium and calcium in the seawater desalination process while removing the sulfate ions and chloride ions. Seawater have been separated the concentrated seawater and desalted seawater by passing on Reverse Osmosis membrane (RO). Using Nano-filtration membrane (NF), We were prepared primary mineral concentrated water that sodium chloride were not removed. By the operation of electro-dialysis (ED) having ion exchange membrane, we were prepared concentrated mineral water (Mineral enriched desalted water) which the sodium chloride is removed. We have produced the high hardness water to meet the drinking water quality standards by diluting the mineral enriched desalted water with deionized water by RO. Reverse osmosis membranes (RO) can separate dissolved material and freshwater from seawater (deep seawater). The desalination water throughout the second reverse osmosis membrane was completely removed dissolved substances, which dissolved components was removed more than 99.9%, its the hardness concentration was 1 mg/L or less and its chloride concentration was 2.3 mg/L. Since the nano-filtration membrane pore size is $10^{-9}$ m, 50% of magnesium ions and calcium ions can not pass through the nano-filtration membrane, while more than 95% of sodium ions and chloride ions can pass through NF membrane. Nano-filtration membrane could be separated salt components like sodium ion and chloride ions and hardness ingredients like magnesium ions and calcium ions, but their separation was not perfect. Electric dialysis membrane system can be separated single charged ions (like sodium and chloride ions) and double charged ions (like magnesium and calcium ions) depending on its electrical conductivity. Above electrical conductivity 20mS/cm, hardness components (like magnesium and calcium ions) did not removed, on the other hand salt ingredients like sodium and chloride ions was removed continuously. Thus, we were able to concentrate hardness components (like magnesium and calcium ions) using nano-filtration membrane, also could be separated salts ingredients from the hardness concentration water using electrical dialysis membrane system. Finally, we were able to produce a highly concentrated mineral water removed chloride ions, which hardness concentration was 12,600 mg/L and chloride concentration was 2,446 mg/L. By diluting 10 times these high mineral water with secondary RO (Reverse Osmosis) desalination water, we could produce high mineral water suitable for drinking water standards, which chloride concentration was 244 mg/L at the same time hardness concentration 1,260 mg/L. Using the linked process with reverse osmosis (RO)/nano filteration (NF)/electric dialysis (ED), it could be concentrated hardness components like magnesium ions and calcium ions while at the same time removing salt ingredients like chloride ions and sodium ion without heating seawater. Thus, using only membrane as RO, NF and ED without heating seawater, it was possible to produce drinking water containing high hardness suitable for drinking water standard while reducing the energy required to evaporation.