Currently, there is no definitive regulation for the appropriate frequency of data sampling in water distribution networks, yet it plays a crucial role in the efficient operation of these systems. This study proposes a new methodology for determining the optimal frequency of data acquisition in water distribution networks. Based on the decomposition of signals using harmonic series, this methodology has been validated using actual data from water distribution networks. By analyzing 12 types of data collected from two points, it was demonstrated that utilizing the factors and cumulative periodograms of harmonic series enables similar accuracy at lower data acquisition frequencies compared to the original signals.

선박에 파울링이 발생되면 운항 중 선박의 저항이 증가하게 되고 이로 인해 연료 소모량도 높아지게 된다. 또한 파울링의 제거에 많은 시간이 필요하게 되어 전체적으로 선박의 유지보수 비용이 증대되는 문제점이 있다. 이러한 문제점을 해결하고 환경오염을 방지 하기 위해 주석과 같은 독성 물질을 포함하지 않는 자기연마형 방오도료를 개발하고 있다. 이와 같은 종래기술은 해수와의 마찰이나 진동이 많이 발생하는 운항 중에는 연마기능이 촉진되어 방오성능이 증대되나, 정박 중과 같이 실제로 파울링이 심화되는 경우에는 해수의 흐름이 없어 연마기능이 저하되어 방오성능이 떨어지는 문제점이 있다. 이러한 문제점을 해결하기 위해 선체의 진동 및 해수의 흐름이 없어서 연마 기능이 저하되는 정박 중에도 진동을 부여하여 연마 기능의 저하를 방지하는 제품을 개발하였다. 개발된 초음파 방오장비의 성능의 신뢰성을 위해 파형발생기의 반복성을 확인하였고 장치의 파울링 제거효율의 정성적인 경향은 시편을 통해 파악하였다. 실험 결과 주파수와 진폭의 반복성의 변동계수 값은 평균 0.2 %, 4.0 %를 나타냈고 시편의 파울링 발생량은 No.5 시편에서 73.3 g으로 가장 많았고 파울링 제거효율은 장치를 설치하지 않은 시편과 비교하여 평균 93.2 % 값을 확인할 수 있었다.

The purpose of this paper is to explore the fishing grounds of trawl fishery, which are operating in the waters around Jeju Island, and to investigate the monthly shifting changes of the explored fishing grounds. Information on AIS of fishing vessels operating near Jeju Island was collected and analyzed from October 16, 2016 to October 16, 2017. Thus, the location of fishing vessels with the same operational characteristics as those in this industry was extracted and displayed on Google Maps' location drawings to analyze the dense distribution of fishing vessels according to the frequency of their appearance. In the distribution of fishing vessels that appeared in October, a wide range of fishing grounds connecting the upper and lower waters of the 221 and 222 sea of fishing area was found to have gradually expanded and increased density, showing the widest range and highest density in December, and then gradually decreasing from January 2017 to near extinction in May. The distribution of fishing vessels that appeared in the left and lower waters of the 243 sea estuary increased not only in November and December, but also in the appearing sea areas gradually moved to the 242 sea and the range of their appearance was extended to the 241 sea. In other words, the highly dense fishing area in December indirectly shows that it is winter fishing grounds for these industries. The distribution of these dense fishing vessels gradually moved north and west with each passing day, reducing their density and reaching a near extinction in August. However, in September, the density was gradually restored again. Fishing vessels that appeared in high density in the northern waters of the 224 sea east of the Yeoseo island in December were thought to be fishing vessels, whose density decreased over time, almost disappeared in May, and reappeared in July and August, showing a certain degree of density, and then decreased again.

Mosquitoes are primary medical insect pests due to their diseases transmission as vectors. In Korea, the insecticide-resistant populations of disease vector mosquito species, such as Anopheles sinensis, Culex pipiens and Culex tritaeniorhynchus, have constantly increased. Thus, management of insecticide resistance to major insecticides including pyrethroids and organophosphates is required for more efficient control of resistant populations. In this study, the quantitative sequencing (QS) protocols were established to detect the frequencies of three mutations (the L1014F on voltage sensitive sodium channel and the G119S and F331W on acetylcholinesterase 1) that are associated with either pyrethroids or organophosphates. Based on the QS protocol using newly designed non-polymorphic primers, resistance allele frequencies (RAFs) were estimated in field populations of An. sinensis, Cx. pipiens and Cx tritaeniorhynchus collected from an identical site in Korea. The dynamics of each resistance allele frequency over time in the same populations were also evaluated.

In the area around Jeju Island, the squid jigging fishery and the hair-tail angling are popular. Therefore, the study on the characteristics of the formation and shift of fishing grounds is very important. We have received and analyzed AIS data of all vessels around Jeju Island from October 16, 2016 to October 16, 2017, and extracted the positions of the fishing vessels with the same operational characteristics as the fishing vessels of their fisheries. The distribution chart of the frequency of fishing vessels appearing in each predefined fishing grid (1 NM × 1 NM) was analyzed. So we took a analogy with the monthly shift of fishing grounds. Many fishing vessels appeared in the seas around Jeju Island from November 2016 to January 2017, and the frequency of their appearance was maintained. In November, however, fishing vessels were mostly concentrated in coastal waters. Yet, the density gradually weakened as they moved into January. From February, the frequency itself began to decline, making it the worst in April. The high concentration of fishing vessels in the waters leading from Jeju Island's northwest coast to south coast in November is believed to be related to the yellowtail fishery that are formed annually in the coastal waters off the island of Marado. In May 2017, the appearance frequency of fishing vessels increased and began to show a concentration in coastal waters around Jeju Island. Fishing vessels began to flock in waters northwest of Jeju Island beginning in July and peaked in August, and by September, fishing vessels were moving south along the coast of Jeju Island, weakening the density and spreading out. Between July and August, fishing vessels were concentrated in waters surrounding Jeju Island, which is believed to be related to the operations of fishing vessels for the squid jigging fishery and the hair-tail angling.

인터넷과 스마트폰의 보급과 함께 사람들은 관심 있는 정보를 포털사이트에서 실시간으로 검색할 수 있게 되었다. 그에 따라 빅데이터가 비정형적으로 형성되고 이를 이용하기 위한 연구 분야가 발전하고 있다. 최근 식품분야 에서도 빅데이터를 활용한 연구의 필요성이 꾸준히 제기 되고 있다. 본 연구는 국내 최대 규모의 포털 사이트인 네이버의 검색 통계를 활용하여, 사람들의 연관 검색어 빈도에 따른 식품안전 사고 원인 식품과 식중독 원인 병원 체들의 관계를 분석하였다. 특히 식중독과 관련된 식품과 식중독 원인 병원체의 포털사이트 키워드 검색 건수와 해당 원인 식품 및 병원체의 뉴스검색 건수를 분석하였으며, 최종적으로 키워드 검색 건수와 실제 식중독 발생 시기의 상관관계를 분석하였다. 분석결과, 일반적으로 식중독 발생 직후 관련 키워드 검색 건수가 증가하는 것으로 나타 났으며, 특별하게 굴과 같은 계절성 식품의 경우 키워드 검색 건수 증가 이후에 식중독 사고가 발생한 것으로 나타났다. 따라서 본 연구결과를 통해 검색 건수가 증가하는 식중독 세균이나 식품들을 식중독 사전 예방적 차원의 정보로 활용할 수 있다면 식중독 사고 발생 가능성을 낮출 수 있을 것으로 사료된다.

본 논문에서는 Euler-Bernoulli Beam(EB-beam) 및 신속 Fourier 변환을 이용하여 수치분석적 빔 모델 및 Co-rotational plane beam EDISON program(CR-beam)을 이용한 빔 모델의 가진주파수 변화에 따른 외팔보의 자유단 진동 연구를 수행하였다. 위의 두 빔 모델에서의 끝단에서는 진동이 시간이 지남에 따라 감소하다가 정상상태에 이르는 것을 확인하였다. 끝단에서 가진주파수가 증가함에 따라 구조적 감쇠에 의해 변위이 감소하는 경향을 보인다. 감쇠를 고려한 EB-beam과 CR-beam가 정상상태로 진입하는 경향이 비슷하나, 가진주파수는 정상상태가 나타나는 시간과 독립적임을 제시한다.

Amphiregulin (AREG), a glycoprotein that is a member of the epidermal growth factor (EGF) family, is expressed by the porcine conceptus and endometrium. AREG genotypes were determined based on an SNP in the intron 3 of the gene. Contradictory effects of AREG genotypes on reproductive traits in different pig breeds were reported previously. G allele had undesirable effect on reproductive trait in Meishan breed, while it had favorable effects in Polish Landrace and Large White. We determined AREG genotypes of 179 pigs including the Duroc, Landrace, Yorkshire, Korean native pig (KNP), and Meishan breeds. Two new SNPs were identified near the previously reported SNP in the intron 3 of AREG. Frequencies of AREG alleles among the Duroc, Landrace, Yorkshire, and KNP sows were significantly different (p<0.001), indicating association between AREG genotypes and pig breeds. The first parity litter size was significantly affected by the breeds (p=0.014), but not by AREG genotypes (p=0.148). However, there were breed and AREG genotype associated trends in the first parity litter size. The first parity litter size appeared to be higher in Duroc and KNP sows with G allele, while it appeared to be lower in Landrace sows with G allele. Significant variability of AREG alleles among pig breeds, for the first time in Duroc and KNP sows, was identified. AREG genotypes may influence reproductive traits differentially for each breed and thus, AREG genotypes may need to be considered when sows are bred to increase litter size.

PURPOSES : The objective was to develop the advanced method which could not explain each observation’s specific characteristic in the present negative binomial method that results in under-estimation of the standard error(t-value inflation) and affects the confidence of whole derived results. METHODS : This study dealt with traffic accidents occurring within interchange segment on highway main line with RPNB(Random Parameter Negative Binomial) method that enables to take account of heterogeneity. RESULTS : As a result, AADT and lighting installation type on the road were revealed to have random parameter and in terms of other geometric variables, all were derived as fixed parameter(same effect on every segment). Also, marginal effects were adapted to analyze the relative effects on traffic accidents. CONCLUSIONS : This study proves that RPNB method which considers each observation’s specific characteristics is better fitted to the accident data with geometrics. Thus, it is recommended that RPNB model or other methods which could consider the heterogeneity needs to be adapted in accident analysis.

본 연구의 목적은 초등학교 과학교과서에 나오는 지구과학 지식에 대한 질문을 분석하는 것이다. 교육대학교 교과목 수업에서 과학교과서에 나오는 지구과학 지식에 대한 교사로서의 질문을 조별 활동을 통해 추출하였다. 질문의 종류와 빈도, 그리고 질문의 인지적 배경 출처를 조사 분석한 결과를 토대로 다음과 같은 결론을 얻었다. 첫째, 지구과학 부문별 질문의 종류와 집중 정도, 그리고 질문의 인지적 배경 출처에 차이가 있었다. 특히 천문관련 부문에서는 다른 부문과는 달리 개별 차시별로 질문 빈도와 집중이 다른 경향을 보이므로 이를 고려한 교수 설계를 할 필요가 있다. 둘째, 인지적 배경 출처로서 '학교' 비율이 가장 높으며, '친구'도 매우 중요한 출처이므로 동료 간 상호작용을 유도하는 협력이 학습에 중요한 요소임을 보여주고 있다. 또한, '인터넷'과 'TV' 같은 대중매체가 '학교'와 비슷한 높은 수준으로 인지적 배경 지식의 출처임을 보여 주고 있어서 이들을 이용한 과학 수업에 대한 고려가 필요하다. 셋째, 차시에 따라 질문의 집중과 종류, 빈도가 다르므로 교사 교육에서 단원별 학습주제에 대한 교육적 접근에서 이를 활용하는 교수방략이 요청된다.

본 논문에서는 아이소-지오메트릭 해석법을 이용하여 고주파수를 가지는 파워흐름 문제에 대하여 연속체 기반 형상 최적설계를 수행하였다. 아이소-지오메트릭 기법을 형상 최적설계에 적용하면, CAD 기하 모델링에서 쓰이던 NURBS 기저 함수가 직접 쓸 수 있기에 정확한 기하학 정보가 수치계산에서 고려되고, 이에 따라 형상 최적설계 관점에서 볼 때, 전통적인 유한요소법에 비해 향상되고 부드러운 설계 섭동량을 가지는 설계 매개화가 가능하게 된다. 즉, 정확한 기하 모델이 응답 해석과 설계민감도 해석에 쓰이게 되고, 이에 따라 설계영역 전체에서 법선 벡터와 곡률이 연속적으로 되게 된다. 결과적으로 정밀한 민감도 해석이 가능하게 된다. 몇 가지 수치예제를 통하여 개발된 아이소-지오메트릭 설계민감도가 유한차분 설계민감도와 비교하여 정확성을 확인할 수 있었으며, 형상 최적설계 문제를 통해서 본 방법론을 적용하여 검증하였다.

PURPOSES: The methods of measuring the sound from the noise source are Pass-by method and NCPX (Noble Close Proximity) method. These measuring methods were used to determine the linkage of TAPL (Total Acoustic Pressure Level) and SPL (Sound Pressure Level) in terms of frequencies. METHODS : The frequency analysis methods are DFT (Discrete Fourier Transform) and FFT (Fast Fourier Transform), CPB (Constant Percentage Bandwidth). The CPB analysis was used in this study, based on the 1/3 octave band option configured for the frequency analysis. Furthermore, the regression analysis was used at the condition related to the sound attenuation effect. The MPE (Mean Percentage Error) and RMSE (Root Mean Squared Error) were utilized for calculating the error. RESULTS: From the results of the CPB frequency analysis, the predicted SPL along the frequency has 99.1% maximum precision with the measured SPL, resulting in roughly 1 dB(A) error. The TAPL results have precision by 99.37% with the measured TAPL. The predicted TAPL results at this study by using the SPL prediction model along the frequency have the maximum precision of 98.37% with the vehicle velocity. CONCLUSIONS: The Predicted SPL model along the frequency and the TAPL result by using the predicted SPL model have a high level of accuracy through this study. But the vehicle velocity-TAPL prediction model from the previous study by using the log regression analysis cannot be consistent with the TAPL result by using the predicted SPL model.

Black porgy and fat greenling are commercially important fish species due to the continuously increasing demand in Korea. When estimating acoustically the fish length by a fish sizing echo sounder, it is of crucial importance to know the target strength (TS) to length dependence. In relation to these needs, the target strength experiments for live fishes were conducted in an acrylic salt water tank using two split-beam echo sounders operating at 70 and 120kHz. The target strength under well-controlled laboratory conditions was simultaneously measured with the swimming movement by digital video recording (DVR) system and analyzed as a function of fish length (L) and frequency (or wavelength λ). Equations of the form TS-alog (L)+blog (1)+c were derived for their TS-length dependence. The best fit regression of TS on fork length for black porgy was TS=20.62 log (L, m)-0.62 log (λ, m)-30.68 (r2=0.77). The best fit regression of TS on fork length for fat greenling was TS=12.06 log (L, m)-5.85 log (λ, m)-22.15 (r2=0.44).

본 논문에서는 고유진동수 조절이 가능한 멀티셀 액체댐퍼를 개발하여 특성을 평가하였다. 본 연구에서 제안한 댐퍼의 기본적인 형태는 기존의 Liquid Column Vibration Absorber(LCVA)와 같다. 그러나 이번에 제안한 액체댐퍼는 기존 LCVA의 수직관을 일정한 면적의 독립된 셀로 나누었으며 이 셀을 각각 밀폐시킬 수 있게 하여 수직관의 면적을 조절하는 방식으로 댐퍼의 고유진동수를 변화시킬 수 있도록 하였다. 이렇게 제작된 액체댐퍼는 밀폐된 셀 개수를 조절하여 진동대 실험을 통해 댐퍼의 고유진동수 특성을 파악하였다. 진동대 실험에서 나온 고유진동수와 이론적으로 산정한 고유진동수를 비교하여 댐퍼의 사용성을 평가하였다. 개발된 액체 댐퍼의 수직관의 면적 조절을 통해 고유 진동수 조절이 용이하여 실제로 사용이 가능함을 확인할 수 있었다.

Aphids feed on host plants by penetrating the stems or leaves with stylets. The feeding behavior of aphids consists of probing, penetration, salivation, and sap ingestion. To assess the effects of sound on feeding behavior, we monitored the stylet activity of the green peach aphid, Myzus persicae (Sulzer), using electrical penetration graph (EPG). The use of EPG was critical for determining the stage, frequency, and duration of feeding in aphids. We played back four acoustic stimuli of sine waves with frequencies of 100, 500, 1000, and 5000 Hz to adult aphids. When the sound was treated, the frequencies of probing, penetration, and salivation increased, whereas the duration of sap ingestion decreased. The 100 Hz and 500 Hz was significantly effective to disturb ingestion of phloem sap. The results of EPG revealed that the acoustic stimuli may restrict aphid feeding by disturbing sap ingestion.

Nontuberculous mycobacteria (NTM) often confounds the interpretation of skin test in tuberculosis diagnosis, resulting in false-positive reaction. And, NTM are emerging pathogens that cause opportunistic infections in both humans and animals. The prevalence of NTM on human disease has been well investigated, whereas that of NTM on animal disease is not well established in Korea. The aim of this study was to determine the prevalence of NTM on cattle, which did not have symptoms of tuberculosis disease. A total of 426 isolates were collected in Korean native cattle and dairy cattle from 2007 to 2010. The most frequently isolated organisms were Mycobacterium peregrimum (n=5, 28%), Mycobacterium fortuitum (n=3, 17%), Mycobacterium intracellulare (n=2, 11%), Mycobacterium phlei (n=1, 5.6%), Mycobacterium terrae (n=1, 5.6%), Mycobacterium llatzerense (n=1, 5.6%), and Norcadia spp. (n=1, 5.6%). It seems to be necessary to further study the prevalence of NTM on environment (water, soil, feces) as well as animals.