• Title/Summary/Keyword: Time-frequency analysis

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Comparison of automatic and manual chamber methods for measuring soil respiration in a temperate broad-leaved forest

  • Lee, Jae-Seok
    • Journal of Ecology and Environment
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    • v.42 no.4
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    • pp.272-277
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    • 2018
  • Background: Studying the ecosystem carbon cycle requires analysis of interrelationships between soil respiration (Rs) and the environment to evaluate the balance. Various methods and instruments have been used to measure Rs. The closed chamber method, which is currently widely used to determine Rs, creates a closed space on the soil surface, measures $CO_2$ concentration in the inner space, and calculates Rs from the increase. Accordingly, the method is divided into automatic or manual chamber methods (ACM and MCM, respectively). However, errors of these methods and differences in instruments are unclear. Therefore, we evaluated the characteristics and difference of Rs values calculated using both methods with actual data. Results: Both methods determined seasonal variation patterns of Rs, reflecting overall changes in soil temperature (Ts). ACM clearly showed detailed changes in Rs, but MCM did not, because such small changes are unknown as Rs values are collected monthly. Additionally, Rs measured using MCM was higher than that using ACM and differed depending on measured plots, but showed similar tendencies with all measurement times and plots. Contrastingly, MCM Rs values in August for plot 4 were very high compared with ACM Rs values because of soil disturbances that easily occur during MCM measurements. Comparing Rs values calculated using monthly means with those calculated using MCM, the ACM calculated values for monthly averages were higher or lower than those of similar measurement times using the MCM. The difference between the ACM and MCM was attributed to greater or lesser differences. These Rs values estimated the carbon released into the atmosphere during measurement periods to be approximately 57% higher with MCM than with ACM, at 5.1 and $7.9C\;ton\;ha^{-1}$, respectively. Conclusion: ACM calculated average values based on various Rs values as high and low for measurement periods, but the MCM produced only specific values for measurement times as representative values. Therefore, MCM may exhibit large errors in selection differences during Rs measurements. Therefore, to reduce this error using MCM, the time and frequency of measurement should be set to obtain Rs under various environmental conditions. Contrastingly, the MCM measurement is obtained during $CO_2$ evaluation in the soil owing to soil disturbance caused by measuring equipment, so close attention should be paid to measurements. This is because the measurement process is disturbed by high $CO_2$ soil concentration, and even small soil disturbances could release high levels into the chamber, causing large Rs errors. Therefore, the MCM should be adequately mastered before using the device to measure Rs.

The Adequacy Analysis of Korean MVNO Policy (MVNO 정책의 타당성 분석)

  • Shin, Jin;Park, Dea-Woo
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2014.10a
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    • pp.926-929
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    • 2014
  • In Korea MVNO was introduced in 2011 when twenty seven years had passed since Korea Mobile Telecom started mobile phone service in 1984. Whithout having its frequency bands and network facilities MVNO can resell the mobile telecom services to the consumers by purchasing MNO's service. That can bring competition more efffective that can lower communication costs through the alternatives. In the early 2000s, the need for the introduction of the MVNO has been raised already by scholars in Korea. But it wasn't until the late 2000s, rate cuts appeared to be a major policy issue, and in 2011 Korean government begin to try to introduce its own MVNO's. In may 2014, MVNO's mobile communication market share reached 6%, but Korea dose not have a firm system yet. However, if government authorities did not insist 3 mobile telecom companies system and recognize global MVNO flow quickly the national cost would be significantly reduced. In the mean time mobile telecom companies have maintained similar billing system and level of service but competed to attract consumers only. It looks like some level of mutual collision and the government cannot help recognizing the situation but it did not do any effective policy improvement effort and government only levied penalties.

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A Study on Pre-service Early Childhood Teachers' Perception of Bullying (예비유아교사의 따돌림 인식에 대한 연구)

  • Bae, Jae-Hyun
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.20 no.5
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    • pp.417-426
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    • 2019
  • This study examined to offer practical implications for the bullying for the prevention and response in early childhood education at the scene of the bullying that occur by to confirm the perception of the bullying to pre-service early childhood teachers. The survey questionnaire was completed by 313 pre-service early childhood teachers. SPSS Win program was used to perform frequency analysis, ANOVA. (1)The perception of bullying were significantly different according to grade and experience of child care practice, classroom observation, education program for taking preventive measure. (2)Teachers' perception about the action that can be seen as bullying followed by 'apply the violence, such as kicking, or were frequent', 'shared in things that often prevents','often to another carrier or shame in front of a friend'. (3)Perception about characteristics of bullying Perpetrators was 'aggressive behavior and talk much' and perception about characteristics of bullying victims was 'shy and not much'. (4)The reason of bullying perpetrators was 'Just for fun without a special reason' and the cause of bullying victims was 'problem of parents' child-rearing attitudes and home environment'. (5)Important institutions to combat bullying prevention followed by teacher, parents and family, community and the nation, preschool educational institution. Teachers guidance content of combat and prevent bullying was 'to be isolated from the class to infants continue to monitor'. Parents guidance content of combat and prevent bullying was 'communicate a lot and attention to children'. Early childhood education institutions guidance content of combat and prevent bullying was 'operations to come up with the bullying prevention education in educational time'. This study indicated that it is necessary to make efforts for increasing perception of bullying in pre-service early childhood teachers.

Review of Non-invasive Interventions for Drooling Problems in Children With Cerebral Palsy: Trends and Analysis of Interventions for Drooling (신경발달장애 아동의 침흘림치료를 위한 비침습적 중재방법에 관한 고찰: 경향 및 중재방법 분석)

  • Jeon, Joo young;Park, Hae Yean
    • Therapeutic Science for Rehabilitation
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    • v.10 no.2
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    • pp.37-51
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    • 2021
  • Objective : The purpose of this study was to analyze non-invasive treatments and drooling assessment methods in children with cerebral palsy and developmental disabilities, who drool. Methods : This study searched two hundred papers published in 2005-2019. Forty-four papers were selected based on their abstract and title, and ten papers were finally selected following a secondary search. Results : The PEDro Scale of the selected papers was high with an average of seven points. As a result of analyzing the overall trends, the study participants were primarily patients with cerebral palsy, and recently, the therapeutic intervention of oral sensory exercise was more actively studied than behavioral modification. Studies of behavioral modification and oral sensory exercise intervention methods were found to have differences in participant age and, cognitive level, number of participants, research design, treatment time, and duration. Studies to confirming the frequency and severity of the drooling measurement method were found to be the main factor. Conclusion : This study analyzed typical behavioral modification and oral sensory exercise interventions as examples of non-invasive therapeutic interventions for children with cerebral palsy and developmental disabilities and provided information to help select appropriate therapeutic intervention methods when planning non-invasive therapy using behavioral modification and oral sensory exercise therapy.

A Study on Joseon Royal Cuisine through Sachanbalgi of the Jangseogak Archives - Focusing on Royal Birthday, Child birth, Weddings and Funerals- (장서각 소장 사찬발기를 통한 조선왕실의 사찬음식 연구 - 탄일, 출산, 가례, 상례를 중심으로 -)

  • Chung, Hae-Kyung;Shin, Dayeon;Woo, Nariyah
    • Journal of the Korean Society of Food Culture
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    • v.34 no.5
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    • pp.508-533
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    • 2019
  • This study investigated the Sachanbalgi, which record the royal feasts given by the royal family of the Joseon Dynasty of Korea. These records are contained within the Gungjung Balgi, which recorded the types and quantity of items used in royal court ceremonies. The Eumsikbalgi is the general name for the records of food found within this document. Using these Eumsikbalgi, and in particular the Sachanbalgi, this study investigated the food eaten and bestowed by the Joseon royal family. The Sachanbalgi describes four categories or occasions of feasts: royal birthdays, childbirth, royal weddings, and funerals. These records allow us to reconstruct who the attendees were and what the table settings and food were for instances not directly indicated in oral records, books, or other documents. The food at these Sachan (feasts) was diverse, being related to the specific event, and its contents varied based on the position of the person who was receiving the food. Usually, Bab (rice) was not found at a Sachanbalgi, and only on two occasions were meals with Bab observed. Specifically, it was served with Gwaktang (seaweed soup) at a childbirth feast. There were seven kinds of soups and stews that appeared in the Sachanbalgi: Gwaktang, Yeonpo (octopus soup), Japtang (mixed food stew), Chogyetang (chilled chicken soup), Sinseonro (royal hot pot), and Yukjang (beef and soybean paste). Nureumjeok (grilled brochette) and Saengchijeok (pheasant), and Ganjeonyueo (pan-fried cow liver fillet) and Saengseonjeonyueo (pan-fried fish fillet) were eaten. Yangjeonyueo, Haejeon, Tigakjeon (pan-fried kelp) and other dishes, known and unknown, were also recorded. Boiled meat slices appeared at high frequency (40 times) in the records; likewise, 22 kinds of rice cake and traditional sweets were frequently served at feasts. Five kinds of non-alcoholic beverages were provided. Seasonal fruits and nuts, such as fresh pear or fresh chestnut, are thought to have been served following the event. In addition, a variety of dishes including salted dry fish, boiled dish, kimchi, fruit preserved in honey, seasoned vegetables, mustard seeds, fish, porridge, fillet, steamed dishes, stir-fried dishes, vegetable wraps, fruit preserved in sugar, and jellied foods were given to guests, and noodles appear 16 times in the records. Courtiers were given Banhap, Tanghap, Myeonhap, wooden bowls, or lunchboxes. The types of food provided at royal events tracked the season. In addition, considering that for feasts food of the royal household was set out for receptions of guests, cooking instructions for the food in the lunchbox-type feasts followed the cooking instructions used in the royal kitchen at the given time. Previous studies on royal cuisine have dealt mostly with the Jineosang presented to the king, but in the Sachanbalgi, the food given by the royal family to its relatives, retainers, and attendants is recorded. The study of this document is important because it extends the knowledge regarding the food of the royal families of the Joseon Dynasty. The analysis of Sachanbalgi and the results of empirical research conducted to reconstruct the precise nature of that food will improve modern knowledge of royal cuisine.

A Study on the Performance Degradation Pattern of Caisson-type Quay Wall Port Facilities (케이슨식 안벽 항만시설의 성능저하패턴 연구)

  • Na, Yong Hyoun;Park, Mi Yeon;Jang, Shinwoo
    • Journal of the Society of Disaster Information
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    • v.18 no.1
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    • pp.146-153
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    • 2022
  • Purpose: In the case of domestic port facilities, port structures that have been in use for a long time have many problems in terms of safety performance and functionality due to the enlargement of ships, increased frequency of use, and the effects of natural disasters due to climate change. A big data analysis method was studied to develop an approximate model that can predict the aging pattern of a port facility based on the maintenance history data of the port facility. Method: In this study, member-level maintenance history data for caisson-type quay walls were collected, defined as big data, and based on the data, a predictive approximation model was derived to estimate the aging pattern and deterioration of the facility at the project level. A state-based aging pattern prediction model generated through Gaussian process (GP) and linear interpolation (SLPT) techniques was proposed, and models suitable for big data utilization were compared and proposed through validation. Result: As a result of examining the suitability of the proposed method, the SLPT method has RMSE of 0.9215 and 0.0648, and the predictive model applied with the SLPT method is considered suitable. Conclusion: Through this study, it is expected that the study of predicting performance degradation of big data-based facilities will become an important system in decision-making regarding maintenance.

Big Data-based Monitoring System Design for Water Quality Analysis that Affects Human Life Quality (인간의 삶의 질에 영향을 끼치는 수질(물) 분석을 위한 빅데이터 기반 모니터링 시스템 설계)

  • Park, Sung-Hoon;Seo, Yong-Cheol;Kim, Yong-Hwan;Pang, Seung-Peom
    • Journal of Korea Entertainment Industry Association
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    • v.15 no.3
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    • pp.289-295
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    • 2021
  • Today, the most important factor affecting the quality of human life is thought to be due to the environment. The importance of environmental monitoring systems to improve human life and improve welfare as the magnitude of the damage increases year by year due to the rapid increase in the frequency of hail, typhoons, collapse of incisions, landslides, etc. Is increasing day by day. Among environmental problems, problems caused by water quality have a very high proportion, and as there is a growing concern that the scale of damage will increase when water pollution accidents occur due to urbanization and industrialization, the demand for social water safety nets is increasing. have. In the last 5 years, 259 cases of water pollution (Han River 99, Nakdong River 31, Geum River 25, Seomjin River and Yeongsan River 19, and 85 others) have occurred in the four major river basins. Caused damage. Therefore, it is required to establish a water quality environment management strategy system based on big data that can minimize the uncertainty of the water quality environment by expanding the target of water quality management from the current water quality management system centered on the four major rivers to small and medium-sized rivers, tributaries/branches, and reservoirs. In this paper, we intend to construct and analyze a water quality monitoring system based on big data that can present useful water quality environment information by analyzing the water quality information accumulated for a long time.

A study on the predictability of acoustic power distribution of English speech for English academic achievement in a Science Academy (과학영재학교 재학생 영어발화 주파수 대역별 음향 에너지 분포의 영어 성취도 예측성 연구)

  • Park, Soon;Ahn, Hyunkee
    • Phonetics and Speech Sciences
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    • v.14 no.3
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    • pp.41-49
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    • 2022
  • The average acoustic distribution of American English speakers was statistically compared with the English-speaking patterns of gifted students in a Science Academy in Korea. By analyzing speech recordings, the duration time of which is much longer than in previous studies, this research identified the degree of acoustic proximity between the two parties and the predictability of English academic achievement of gifted high school students. Long-term spectral acoustic power distribution vectors were obtained for 2,048 center frequencies in the range of 20 Hz to 20,000 Hz by applying an long-term average speech spectrum (LTASS) MATLAB code. Three more variables were statistically compared to discover additional indices that can predict future English academic achievement: the receptive vocabulary size test, the cumulative vocabulary scores of English formative assessment, and the English Speaking Proficiency Test scores. Linear regression and correlational analyses between the four variables showed that the receptive vocabulary size test and the low-frequency vocabulary formative assessments which require both lexical and domain-specific science background knowledge are relatively more significant variables than a basic suprasegmental level English fluency in the predictability of gifted students' academic achievement.

COVID-19-related Korean Fake News Detection Using Occurrence Frequencies of Parts of Speech (품사별 출현 빈도를 활용한 코로나19 관련 한국어 가짜뉴스 탐지)

  • Jihyeok Kim;Hyunchul Ahn
    • Journal of Intelligence and Information Systems
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    • v.29 no.2
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    • pp.267-283
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    • 2023
  • The COVID-19 pandemic, which began in December 2019 and continues to this day, has left the public needing information to help them cope with the pandemic. However, COVID-19-related fake news on social media seriously threatens the public's health. In particular, if fake news related to COVID-19 is massively spread with similar content, the time required for verification to determine whether it is genuine or fake will be prolonged, posing a severe threat to our society. In response, academics have been actively researching intelligent models that can quickly detect COVID-19-related fake news. Still, the data used in most of the existing studies are in English, and studies on Korean fake news detection are scarce. In this study, we collect data on COVID-19-related fake news written in Korean that is spread on social media and propose an intelligent fake news detection model using it. The proposed model utilizes the frequency information of parts of speech, one of the linguistic characteristics, to improve the prediction performance of the fake news detection model based on Doc2Vec, a document embedding technique mainly used in prior studies. The empirical analysis shows that the proposed model can more accurately identify Korean COVID-19-related fake news by increasing the recall and F1 score compared to the comparison model.

A Study on the Frequency of Traffic Accidents by Traffic Signal Timing: Focused on Daejeon (『신호현시 표출 방법』에 따른 교통사고 발생빈도 분석 연구: 대전광역시 관내 중심으로)

  • So-sig Yoon;Min-ho Lee;Choul-ki Lee
    • The Journal of The Korea Institute of Intelligent Transport Systems
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    • v.22 no.3
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    • pp.20-37
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    • 2023
  • Although traffic signal installations are continuously expanding, the effect of preventing traffic accidents remains unverified. Totally, 7,045 traffic accident data (such as signal violations) registered with TCS were manually searched for a 7-year period from 2013 to 2019 for 1,602 traffic signals in Daejeon Metropolitan City. The top 20 traffic accident intersections were identified, the traffic accident investigation records and field maps were viewed to compare the driving direction and signal phase of the violated vehicle, and the cause of the traffic accident was divided into insufficient signal operation design (operation) and driver negligence (intentional). Results of the analysis revealed that 75% of traffic accidents occurred in thru-left-turn traffic signals and overlap; moreover, extending the yellow time or operating all red signals due to countermeasures against traffic accidents occurring in yellow signals resulted in reduced traffic accidents. Data indicated that Permissive Left Turn requires improvement with the signal operation. In addition, since The Korean National Police Agency is not computerized for traffic accident sites and signal-related data, the lack of manpower necessitates improvement and utilization of TCS when establishing traffic accident prevention measures. It is believed that it will contribute to signal operation by analyzing vast amounts of data collected in the field and presenting improvement measures.