Due to the decrease in coastal productivity and deterioration in the quality of ecosystem which result from the excessive overfishing of fisheries resources and the environmental pollution, fisheries resources in the Korean waters hit the dangerous level in respect of quantity and quality. In order to manage sustainable and effective fisheries resources, it is necessary to suggest the potential yield (PY) for clarifying available fisheries resources in the Korean waters. So far, however, there have been few studies on the estimation methods for PY in Korea. In addition, there have been no studies on the comparative analysis of the estimation methods and the substantial estimation methods for PY targeted for large marine ecosystem (LME) For the reasonable management of fisheries resources, it is necessary to conduct a comprehensive study on the estimation methods for the PY which combines population dynamics and ecosystem dynamics. To reflect the research need, this study conducts a comparative analysis of estimation methods for the PY in the Korean waters of the East Sea to understand the advantages and disadvantages of each method, and suggests the estimation method which considered both population dynamics and ecosystem dynamics to supplement shortcomings of each method. In this study, the maximum entropy (ME) model of the holistic production method (HPM) is considered to be the most reasonable estimation method due to the high reliability of the estimated parameters. The results of this study are expected to be used as significant basic data to provide indicators and reference points for sustainable and reasonable management of fisheries resources.

Purpose: The research that combines qualitative and quantitative methods are recently received attention in nursing academia and the number of research on mixed method is increased. The purpose of the study was to understand and discuss the application of mixed method research (MMR). Methods: This study provided the concept, research design, justification, and systematic issues of MMR through the literature review and researcher’s analytical thinking. Results: MMR was generally accepted in the literature as a new and comprehensive methodology. MMR was developed from the philosophical foundation on pragmatism. The designs of MMR and notation, mixing strategies, strategies for sampling and data analysis, and validity of MMR were examined. These were continued to be the issues including epistemology and pragmatic stances of MMR, primary point of interface for mixing, the level of interaction between different method (qualitative and quantitative), and more proper langue than ‘mixed’ etc. of MMR. Conclusion: In spite of those issues, MMR is solidified it’s position as multi-strategy research in the aspect of expansion of qualitative and quantitative methods with triangulation. I recommended that the researcher should apply the MMR after considering of epistemological assumptions and possibility evaluation of the synergy effects to his or her research for the merits of extensive results of MMR.

This study considers zone-based registration (ZBR) and distance-based registration (DBR). A mobile station performs location registration whenever the MS reaches a new zone or the specified distance. These two schemes seem to be similar but, in DBR, the mobile station (MS) is in the center of the location area right after location registration differently from in ZBR. In this study, we point out some problems of the previous analysis method and propose an improved analysis method of ZBR and DBR. Using the improved analysis method, we show that the previous analysis includes some problems, and that the performances of two registration methods in our study are enhanced more than in the previous study. This results of this study should be useful to analyze the performance of various location registration schemes.

MOF는 높은 표면적, 균일한 공극, 크기를 가지는 새로운 클래스의 porous material 이다. MOF는 금속과 organic linker가 coordination 결합에 의해 연결되어 있고, 온도에 대한 강한 안정성을 나타내고, 높은 표면적 때문에 촉매, 분리, 개스저장 등 다양한 분야에 적용될 수 있는 잠재력이 풍부하다. MOF는 zeolite보다 높은 표면적을 가지고 작용기를 organic linker에 따라 쉽게 바꿀 수 있는 장점 때문에 최근에 많은 관심을 받게 되었다. 다양한 MOF가 합성되었고 CO2/N2 선택도, 흡착량, 수분과 산성가스에 대한 안정성이 분석되었다. 최종적으로 선택된 MOF는 폴리머와 결합하여 하이브리드 멤브레인을 만드는 데에 사용되었다.

V-Coupling is used as a mechanical fastener to connect the turbine housing and the bearing housing in a turbocharger. The back plate is located between the turbine housing and the bearing housing, which is compressed by the bolt clamping force of coupling to prevent gas leakage under turbocharger operation. This paper presents the theoretical and analytical methods to predict the sealing performance by calculating the contact pressures on the back plate. The mathematical model was constructed to derive the contact force on the back plate by considering the force transfer mechanism. And, finite element analysis was carried out to predict the contact pressures by applying the bolt load in the coupling system. As a result, the analysis results of the mathematical model are well consistent with the results of the finite element analysis. Therefore, in the early design stage of turbocharger coupling, mathematical model would be helpful to determine the design parameters.

최근 합성첨가물에 대한 소비자들의 거부감이 증가하면서 천연물 유래하는 항산화제, 항균제 등의 개발에 대한 연구가 증가하고 있다. 어성초(Hottuynia cordata)는 흔히 약모밀로 불리는 다년생 초본의 야생약초로서, 항균, 항암, 항바이러스 등의 다양한 생리활성 기능이 있다고 알려져 있으며, 이러한 다양한 효능은 어성초 부위와 추출 방법에 따라 다양한 생리활성물질 때문으로 알려져 왔다. 본 연구에서는 어성초의 잎과 뿌리를 이용하여 열수 추출과 70% 에탄올 추출을 하면서 초음파(ultrasonication) 처리 유무에 따른 추출물의 항산화 및 항균 효과를 비교하였다. 열수 추출에서는 건조된 잎줄기와 뿌리 분말 30 g을 300 mL의 증류수에 넣고, 80℃에서 24시간 추출하여 상등액을 취하고, 다시 같은 양의 증류수로 3회 반복하여 추출하였다. 용매 추출은 각 분말 30 g을 300 mL의 70% 에탄올에 넣고 밀폐시킨 후 40℃ 오븐에서 24시간 추출한 후 상등액을 취하고, 같은 방법으로 3회 반복하여 추출하였다. 열수 추출과 용매 추출 방법에서 초음파 처리에 의한 효과를 비교하기 위해 분말을 증류수 또는 에탄올에 침지 시킨 후 probe type의 초음파기로 20분 동안 처리 한 후 24시간 동안 추출하였다. 추출물은 감압 농축 후 동결건조하여 항산화 및 항균 효과를 평가하였다. ABTS 라디칼 소거활성 결과 잎줄기 추출물이 뿌리 추출물에 비해 항산화 효과가 우수하였고, 열수 추출보다는 에탄올 추출이 효과가 높았으며, 초음파 처리를 병행한 경우 유의적인 증가를 보였다. 잎줄기를 초음파를 병행한 에탄올 추출조건에서 RC50값이 1.09 mg/mL로 가장 낮은 값을 나타내었다.

콩나물(Glycine max L. Merrill)은 우리 고유의 전통식품으로서 무침, 국, 찌개, 밥 등 다양한 방법으로 이용되고 있으며 최근에는 편리를 추구하는 바쁜 현대인들을 위하여 콩나물의 반조리식품화 또는 가공식품화의 형태로 이용성이 증가되고 있다. 이에 따라 소비자의 기호에 맞는 고품질 콩나물의 생산을 위하여 콩나물 콩의 생육특성, 발아특성에 대한 연구가 진행되어 왔으나 생 콩나물의 조리 후 조직감 특성에 관한 연구는 부족한 실정이다. 특히 콩나물의 조직감 측정 시의 사용하는 프르브와 측정법에 따라 가공처리에 따른 조직감의 유의차가 다르게 나타나므로 가열처리에 따른 콩나물의 조직감의 변화를 수치적으로 평가하기가 어렵다. 이와 같이 가열처리에 따른 콩나물 조직감의 변화를 객관적인 방법으로 평가하기 위하여 본연구에서는 콩나물은 파우치에 물과 함께 포장한 것과 진공포장 한 것을 84 ℃에서 20 분간 가열처리 하여 실린더형과 칼날형의 프로브를 이용하여 조직감 특성을 확인하였다. 콩나물 머리와 줄기의 조직감 특성은 각각 deformation 30%와 60%의 조건일 때 test speed 0.5 mm/s 에서 진행하였으며, 부정형인 콩나물의 머리를 고려하기 위하여 engineering stress와 true stress를 비교하였다. 콩나물 머리의 크기는 버니어 캘리퍼스로 측정하여 deformation 이전 콩나물의 전체 높이 및 긴 반지름, 짧은 반지름을 기준으로 30% deformation 일 때 해당하는 변수를 이용하였다. 가열처리 방법에 따른 콩나물 머리의 조직감은 실린더형 프로브로 측정 시 유의적 차이가 없었으나 칼날형 프로브를 이용하여 일정한 두께로 조직감을 측정하였을 때 유의적 차이를 확인하였다(p<0.05). 또한 콩나물의 줄기도 가열처리 방법에 따라 칼날형 프로브로 측정시 유의적 차이가 있는 결과값을 확인하였다. 이에 따라 칼날형 프로브를 이용한 가열처리 방법에 따른 콩나물 머리의 engineering stress 결과 값은 유의적 차이가 없었으며, 30% deformation 시에 해당하는 변수를 통하여 도출한 콩나물 머리의 면적이 고려된 true stress 결과 값은 가열처리 방법에 따라 각각 89.08 g ± 10.03, 68.16 g ± 5.93으로 유의적 차이를 보였다. 그리고 콩나물의 줄기는 engineering stress와 true stress 결과 값 모두에서 유의적 차이를 확인하였으며, 두 측정법 간에는 유의차(p<0.05)가 없음을 확인하였다. 따라서 콩나물의 머리와 줄기 모두 칼날형 프로브를 이용하는 것이 가열처리에 따른 콩나물의 특성을 유의미하게 판별할 수 있는 방법이 될 수 있음을 확인하였다.

The purpose of this study is focused on evaluating the flexural behavior of concrete beam, which are arranged by mechanically spliced reinforcing bar. To compare the existent lapping method with newly registered splicing method, four cases of concrete beam are tested to be failed flexurally by monotonic loading. Based on test results, ductility of specimen mechanically all spliced by parallel threaded coupler is approximately 4 times greater than those of other specimens.

Phosphorus (P) is a limited, essential, and irreplaceable nutrient for the biological activity of all the living organisms. Sewage sludge ash (SSA) is one of the most important secondary P resources due to its high P content. The SSA has been intensively investigated to recover P by wet chemicals (acid or alkali). Even though H2SO4 was mainly used to extract P because of its low cost and accessibility, the formation of CaSO4 (gypsum) hinders its use. Heavy metals in the SSA also cause a significant problem in P recovery since fertilizer needs to meet government standards for human health. Therefore, P recovery process with selective heavy metal removal needs to be developed. In this paper some of the most advanced P recovery processes have been introduced and discussed their technical characteristics. The results showed that further research is needed to identify the chemical mechanisms of P transformation in the recovery process and to increase P recovery efficiency and the yields.

Almost all buildings and infrastructures made of advanced composite materials are fabricated without proper design. Unlike airplanes or automobiles, prototype test is impossible. One cannot destroy 10 story buildings or 100-meter long span bridges. People try to build 100-story buildings or several thousand meter long span bridges. In order to realize "composites in construction", the following subjects must be studied in detail, for his design. Simple method of analysis, Folded plate theory, Size effects in failure, and Critical natural frequency. Unlike the design procedure with conventional materials, his design should include material design, selection of manufacturing methods, and quality control methods, in addition to the fabrication method. In this paper, folded plate theory are presented for practicing engineers.

본 연구는 하절기 ‘매향’ 딸기 자묘의 삽목 번식에 적 절한 관수 방법을 구명하기 위해 수행되었다. 딸기 자묘의 삽수는 24구 딸기 전용 포트(24구, 60 × 34 × 10cm) 에 상업용 혼합 상토(Tosilee)를 이용하여 삽목하고, 반 밀폐형 소형비닐터널에 위치시켰다. 각각의 반 밀폐형 소형터널의 처리는 다음과 같이 처리했다; 대조구(무처 리), 두상관수(하루 두 번), 매트관수(하루 두 번), 그리 고 안개관수(8:00시부터 18:00시까지 30분 온/오프 설정). 딸기 자묘는 반 밀폐형 소형터널 내에서 8일 동안 발근을 하였고, 그 이후 플라스틱 필름을 제거 하였다. 삽목 후 61일째에 초장, 근장, 1차 근수, 엽병장, 엽장, 엽폭, 크라운 직경, 엽록소 값, 엽면적, 지상부와 지하부의 생 체중 및 건물중을 측정하였다. 터널 내의 하루 평균 상 대습도는 각각 안개관수, 두상관수, 매트관수, 대조구순 으로 72.5, 56.3, 45.8, 그리고 29%를 나타냈다. 그러나 공기온도는 모든 처리에서 유사하였다. 딸기 자묘의 4일 째와 8일째 발근율은 두상관수와 안개관수 처리에서 유 의적으로 높았다. 초장, 엽병장, 크라운 직경, 엽면적은 두상관수와 안개관수 처리에서 높은 값을 나타냈다. 게다가 지상부의 생체중 및 건물중은 다른 처리에 비해 두상관수와 안개관수 처리에서 무거웠다. 지하부의 건물 중은 안개관수 처리에서 유의적으로 무거웠다. 하지만 근장, 1차 근수, 엽록소 값, 지하부의 생체중은 모든 처 리구에서 유의적인 차이를 나타내지 않았다. 결과적으로, ‘매향’ 딸기의 삽목 번식 시 생육과 발근율은 두상관수 와 안개관수 처리에서 가장 효과적인 것으로 나타났다.

The purpose of this study is to pushover analyze existing reinforced concrete(RC) frames strengthened by L-type precast concrete(PC) wall panels. Cyclic loading tests were performed on the partially infilled reinforced concrete(RC) frames by L-type PC wall panels. Based on the results of experimental test, the nonlinear pushover analysis was practiced by using a computer program. The analysis models were designed with two ways according to the test result. The PC wall panel and the RC column exhibited almost composite behavior by using brace when push loading applied. The two structures also exhibited independent behavior when pull loading applied. The results of pushover analysis models generally conform to the experimental results. The ratios of the maximum lateral load measured in the strengthened specimens from the analysis varied between 0.93 and 1.01 in forward cycles, and between 0.84 and 0.90 in backward cycles. The initial stiffness values of the analysis were less than the test values for all strengthened specimens. The ratio of the initial stiffness obtained through testing compared to the values from the analysis varied between 0.72 and 0.90.

동남아시아에 발생하던 등검은말벌은 최근 국내 뿐만 아니라 프랑스와 일본, 유럽 전역으로 확산되어 전 세계 양봉 산업에 극심한 피해를 주고 있다. 등검은말벌을 방제하기 위해 다양한 방제 방법들이 연구되고 있으며, 그 중 말벌 유인제에 대해 국제적으로 많은 연구가 진행되어 왔으나 이 역시 지속적인 개발이 필요한 실정이다. 따라서 본 연구에서는 시판 유인제와 최근 (주)다목에코텍에서 새롭게 개발한 신규 개발 유인제에 대한 효능 검정을 수행하였 고 양봉장에 출현하는 국내 발생 말벌속의 발생양상을 조사하였다. 담양 1개소와 곡성 2개소에 기존 유인제과 신규 유인제를 장착한 포획기를 각 3쌍씩 설치하여 2016년 9월부터 11월말까지 주 1~2회 관찰하였다. 그 결과 국내 발생 말벌속 중 등검은말벌(7,787 개체)이 가장 많이 포획되었고, 다음으로 장수말벌, 말벌, 좀말벌, 꼬마장수말벌, 털보말벌 순으로 포획되었다. 두 유인제의 포획력 검정 결과, 신규 개발 유인제가 통계적으로 유의하게(P < 0.01) 등검은말벌 포획력이 높음을 보였다.

An, Soyoung. 2018. “An Analysis of University Students' English-Learning Motivation Change through Portfolio Assessment”. The Sociolinguistic Journal of Korea 26(1). 251~275. This study aims to analyze university students' English-learning motivation through making a learning portfolio. I conducted an experiment to know whether motivation could be changed by different assessment systems, a result-oriented assessment and a process-oriented assessment. First, there were no statistically significant differences in English-learning motivation between the two groups subject to a result-oriented assessment and a process-oriented assessment by independent T-test. Second, the variable “attitudes toward learning English” significantly changed when students created a learning portfolio by paired T-test. Students showed their preferences for studying English through an authentic learning portfolio method. Therefore, even though the new assessment system such as a portfolio assessment brings us innovation, the assessment system had a partial impact on students' English-learning motivation.

Intermittent demand is a demand with a pattern in which zero demands occur frequently and non-zero demands occur sporadically. This type of demand mainly appears in spare parts with very low demand. Croston’s method, which is an initiative intermittent demand forecasting method, estimates the average demand by separately estimating the size of non-zero demands and the interval between non-zero demands. Such smoothing type of forecasting methods can be suitable for mid-term or long-term demand forecasting because those provides the same demand forecasts during the forecasting horizon. However, the smoothing type of forecasting methods aims at short-term forecasting, so the estimated average forecast is a factor to decrease accuracy. In this paper, we propose a forecasting method to improve short-term accuracy by improving Croston’s method for intermittent demand forecasting. The proposed forecasting method estimates both the non-zero demand size and the zero demands’ interval separately, as in Croston’s method, but the forecast at a future period adjusted by binomial weight according to occurrence probability. This serves to improve the accuracy of short-term forecasts. In this paper, we first prove the unbiasedness of the proposed method as an important attribute in forecasting. The performance of the proposed method is compared with those of five existing forecasting methods via eight evaluation criteria. The simulation results show that the proposed forecasting method is superior to other methods in terms of all evaluation criteria in short-term forecasting regardless of average size and dispersion parameter of demands. However, the larger the average demand size and dispersion are, that is, the closer to continuous demand, the less the performance gap with other forecasting methods.

This experiment was conducted at Suwon, Korea from 2013 to 2015. The objective of this study was to establish the optimum seeding rate, and to clarify the nitrogen fertilizer level for rye seed production in central and north area of Korea. We used Korean rye cultivar ‘Gogu’ for this test. We employed a split-plot design with three replications. The main plots were designed by three seeding levels (3, 5 and 7 kg 10a-1), but other sub-plots were randomly seeded. The plots were treated with three different nitrogen fertilizer levels (3, 6 and 9 kg 10a-1). The percentage of productive tiller, number of grain per spike, fertility rate, 1 liter weight, and 1000-grain weight decreased as seeding rate increased from 3 kg 10a-1 to 7 kg 10a-1, whereas the number of spike per ㎡ increased. Therefore the grain yields of rye had less of an effect by increasing seeding rate. There was an increase in number of spike per ㎡, number of grain per spike, and fertility rate as nitrogen fertilizer level increased from 3 kg 10a-1 to 9 kg 10a-1, but grain yields significantly not affected by the interaction of seeding rate × nitrogen fertilizer levels. However, the best seeding rate and nitrogen fertilizer level for rye seed production were 5 kg and 5∼6 kg 10a-1, respectively, considering seed and fertilizer reduction and the prevention of pollution by excess fertilization.