• Title/Summary/Keyword: Periodic topics

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An Analysis of STS Contents in the High School Chemistry(II) Textbook (화학II 교과서의 STS 내용 분석)

  • Kim, Jung-Tae;Kim, Yun-Hi;Moon, Seong-Bae
    • Journal of the Korean Chemical Society
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    • v.46 no.1
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    • pp.90-96
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    • 2002
  • The STS contents, emphasized in the 6th curriculum, in the chemistry textbooks(II) were analyzed. The STS contents in textbooks showed average value of 2.7%. The chapter of ‘chemical bond and compound' were included 3.8% of STS contents. And the chapter of ‘atomic structure and periodic table', ‘state of material and solution', ‘science of material', and ‘chemical reaction' contained 3.2%, 2.2%, 1.9%, and 1.9% of STS contents, respectively. When the STS contents were analyzed by STS topics of Piel, the results are as follows; 33.7% on effect of technological developments, 27.5% on environmental quality and utilization of natural source, 19.6% on human engineering, 13.8% on energy, and 5.4% on sociality of science. However, there were no topics on population, space research and national defense. When the STS contents were analyzed by student activities of SATIS, most of the activities were research and case study. There were few field activities of practical investigation, problem solving and decision making, research design and stimulation. There were no activities of role play.

Delta Development in the Nakdong River Estuary: a Literature Survey (낙동강 하구역 삼각주 발달에 관한 문헌 고찰 연구)

  • Yoon, Han-Sam;Yoo, Chang-Ill;Kang, Yoon-Koo;Ryu, Cheong-Ro
    • Journal of Ocean Engineering and Technology
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    • v.21 no.2 s.75
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    • pp.22-34
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    • 2007
  • We present basic data for developing new research topics and closely examine the existing data on the development and organization of the Nakdong River Estuary Delta by analyzing various studies of the area, including ocean engineering, coastal engineering, ocean environmental engineering, geomorphological, and geological studies. We first defined the general concepts related to the estuary and delta and reviewed the historical development of the Nakdong River Estuary Delta over the past 100 years. We then examined the origin and core elements of the estuary deposits that constitute the delta. In addition, we scrutinized the main factors affecting the development of the delta and analyzed existing research on delta development mechanisms by core researchers. The construction of an estuary barrage is one of the main factors effecting estuarine circulation and has altered the physical oceanic environment, area of deposition, atmospheric environment, and vegetation community of the delta. These factors affect the estuary circulation in turn, altering the delta. Along the Nakdong River, an unsteady-state sandy barrier appears at approximately three times the distance of the wavelength of incident offshore waves, and this terrain forms approximately 10-15 years after reclamation in the interdistributary upper stream and transforms the shoreline. It is necessary to develop a technique to predict terrain change that reproduces the erosion and accumulation of estuarine deposits. To determine the parameters and variables necessary to reproduce this system, continuous on-site monitoring is necessary. The existing research did not fully examine the terrain changes in Nakdong River Estuary or the periodic developmental characteristics. To understand the future process of estuary delta development, it is necessary to establish an integrated management system.

Detecting cell cycle-regulated genes using Self-Organizing Maps with statistical Phase Synchronization (SOMPS) algorithm (SOMPS 알고리즘을 이용한 세포주기 조절 유전자 검출)

  • Kang, Yong-Seok;Bae, Cheol-Soo
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.13 no.9
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    • pp.3952-3961
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    • 2012
  • Developing computational methods for identifying cell cycle-regulated genes has been one of important topics in systems biology. Most of previous methods consider the periodic characteristics of expression signals to identify the cell cycle-regulated genes. However, we assume that cell cycle-regulated genes are relatively active having relatively many interactions with each other based on the underlying cellular network. Thus, we are motivated to apply the theory of multivariate phase synchronization to the cell cycle expression analysis. In this study, we apply the method known as "Self-Organizing Maps with statistical Phase Synchronization (SOMPS)", which is the combination of self-organizing map and multivariate phase synchronization, producing several subsets of genes that are expected to have interactions with each other in their subset (Kim, 2008). Our evaluation experiments show that the SOMPS algorithm is able to detect cell cycle-regulated genes as much as one of recently reported method that performs better than most existing methods.

A Clinical Practice Guideline for Ma-huang(Ephedra sinica) Prescription in Obesity (비만치료 및 체중감량에서의 적절한 마황 사용에 대한 임상 진료지침 개발)

  • Kim, Ho-Jun;Han, Chang-Ho;Lee, Eui-Ju;Song, Yun-Kyung;Shin, Byung-Cheul;Kim, Yun-Kyung
    • Journal of Korean Medicine for Obesity Research
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    • v.7 no.2
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    • pp.27-37
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    • 2007
  • Background Clinical practice guidelines (CPG) are systematically developed statements to assist practitioners and patients on healthcare decisions. They provide recommendations for the average patient, which should take into account individual clinical judgment and the patient's values and expectations. Ephedra has sympathomimetic effect and has been used for weight loss worldwide. However, its safety is controversial especially in autonomic and cardiovascular systems. Therefore, the need of appropriate CPG for ephedra prescription in obesity was advocated in Korean Traditional Medicine. Methods The committee comprised of specialists of obesity, oriental herbology, oriental cardiology, constitutional medicine. The committee collected all relevant references about adverse effect and safety of ephedra in the forms of meta-analysis, systematic review, randomized controlled trial, case-control study and observational study from international and domestic databases and paper journals. 11 English- and 5 Korean-language references were gathered and categorized by PICO (Patient, Intervention, Comparison, Outcome) method. We could not complete strength of recommendation which should be clarified according to the evidence grade estimation. Result The first version of CPG for ephedra prescription in obesity was issued by Korean Oriental Association for Study of Obesity. It includes topics of introduction, pharmacokinetics, side effects and adverse events, constitutional aspect and recommendations for dose, indication and contraindication. Conclusion There should be periodic upgrade of this CPG from now on. Although there are some drawbacks in this version of CPG, it has significance as the first CPG in Korean Traditional Medicine.

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A Study on the Durability of Manure Composting Facilities (축분 퇴비화 시설 내구성에 관한 조사연구)

  • Hong, Ji-Hyung
    • Journal of Animal Environmental Science
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    • v.16 no.1
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    • pp.13-20
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    • 2010
  • Manure compost is a main product from animal wastes in Korea. Solid manure is usually treated by aerobic composting at manure composting facilities for land reinforcement. Agricultural use of manure compost as organic fertilizer resources, mainly manure compost, is now recommended in Korea. This study investigated the evaluation of durability about the manure composting machinery and structures which was controlled by aeration and periodic agitating. The questionnaire addressed three main topics as follows: operating practices, machinery and maintenance of the manure composting facilities are being operated. A total of the 22 manure composting facilities in an agricultural cooperative were surveyed. The results obtained in this survey were summarized as follow: The major causes of manure composting apparatus trouble were corrosion and wear, overloading and foreign matter etc. The highly trouble frequency of the agitator, packer and conveyor were chain, agitating blade and shaft, motor and screw vane, respectively. These analytical results can be used as basic information to establish the maintenance control methods and durability standard of manure composting facility.

Analysis of Research Trends of 'Word of Mouth (WoM)' through Main Path and Word Co-occurrence Network (주경로 분석과 연관어 네트워크 분석을 통한 '구전(WoM)' 관련 연구동향 분석)

  • Shin, Hyunbo;Kim, Hea-Jin
    • Journal of Intelligence and Information Systems
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    • v.25 no.3
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    • pp.179-200
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    • 2019
  • Word-of-mouth (WoM) is defined by consumer activities that share information concerning consumption. WoM activities have long been recognized as important in corporate marketing processes and have received much attention, especially in the marketing field. Recently, according to the development of the Internet, the way in which people exchange information in online news and online communities has been expanded, and WoM is diversified in terms of word of mouth, score, rating, and liking. Social media makes online users easy access to information and online WoM is considered a key source of information. Although various studies on WoM have been preceded by this phenomenon, there is no meta-analysis study that comprehensively analyzes them. This study proposed a method to extract major researches by applying text mining techniques and to grasp the main issues of researches in order to find the trend of WoM research using scholarly big data. To this end, a total of 4389 documents were collected by the keyword 'Word-of-mouth' from 1941 to 2018 in Scopus (www.scopus.com), a citation database, and the data were refined through preprocessing such as English morphological analysis, stopwords removal, and noun extraction. To carry out this study, we adopted main path analysis (MPA) and word co-occurrence network analysis. MPA detects key researches and is used to track the development trajectory of academic field, and presents the research trend from a macro perspective. For this, we constructed a citation network based on the collected data. The node means a document and the link means a citation relation in citation network. We then detected the key-route main path by applying SPC (Search Path Count) weights. As a result, the main path composed of 30 documents extracted from a citation network. The main path was able to confirm the change of the academic area which was developing along with the change of the times reflecting the industrial change such as various industrial groups. The results of MPA revealed that WoM research was distinguished by five periods: (1) establishment of aspects and critical elements of WoM, (2) relationship analysis between WoM variables, (3) beginning of researches of online WoM, (4) relationship analysis between WoM and purchase, and (5) broadening of topics. It was found that changes within the industry was reflected in the results such as online development and social media. Very recent studies showed that the topics and approaches related WoM were being diversified to circumstantial changes. However, the results showed that even though WoM was used in diverse fields, the main stream of the researches of WoM from the start to the end, was related to marketing and figuring out the influential factors that proliferate WoM. By applying word co-occurrence network analysis, the research trend is presented from a microscopic point of view. Word co-occurrence network was constructed to analyze the relationship between keywords and social network analysis (SNA) was utilized. We divided the data into three periods to investigate the periodic changes and trends in discussion of WoM. SNA showed that Period 1 (1941~2008) consisted of clusters regarding relationship, source, and consumers. Period 2 (2009~2013) contained clusters of satisfaction, community, social networks, review, and internet. Clusters of period 3 (2014~2018) involved satisfaction, medium, review, and interview. The periodic changes of clusters showed transition from offline to online WoM. Media of WoM have become an important factor in spreading the words. This study conducted a quantitative meta-analysis based on scholarly big data regarding WoM. The main contribution of this study is that it provides a micro perspective on the research trend of WoM as well as the macro perspective. The limitation of this study is that the citation network constructed in this study is a network based on the direct citation relation of the collected documents for MPA.

Diurnal Effect Compensation Algorithm for a Backup and Substitute Navigation System of GPS (GPS 백업 및 대체 항법을 위한 지상파 신호의 일변효과 보상 방안)

  • Lee, Young-Kyu;Lee, Chang-Bok;Yang, Sung-Hoon;Lee, Jong-Koo;Kong, Hyun-Dong
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.33 no.12A
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    • pp.1225-1232
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    • 2008
  • In this paper, we describe a compensation method of diurnal effect which is one of the factors giving large effect on the performance when using ground-wave signals like Loran-C for a backup and substitute navigation system of global satellite navigation system such as GPS, and currently many researches of the topics are doing in USA and in Europe. In order to compensate diurnal effect, we find periodic frequency components by using the Least Square Spectral Analysis (LSSA) method at first and then compensate the effect by subtracting the estimated compensation signal, obtained by using the estimated amplitude and phase of the individual frequency component, from the original signal. In this paper, we propose a simple compensation algorithm and analysis the performance through simulations. From the results, it is observed that the amplitude and phase can be estimated with under 5 % and 0.17 % in a somewhat poor receiving situation with 0 dB Signal to Noise Ratio (SNR). Also, we analyze the obtainable performance improvement after compensation by using the measured Loran-C data. From the results, it is observed that we can get about 22 % performance improvement when a moving average with 5 minutes interval is employed.