This paper aims to introduce a case of improving the performance of aged naval ships' Identification Friend or Foe(IFF) equipment from Mode 4 to Mode 5, thereby enhancing operational capabilities and overcoming integration limitations. Since 2019, South Korea has been conducting a project to replace IFF equipment across the entire military, categorized into naval ship, air force aircraft, surveillance and reconnaissance, and protection. Among these, three naval classes without combat systems required not only an upgrade of their IFF equipment from Mode 4 to Mode 5 but also an integration capability that would allow them to maintain the same fire control procedures by linking with existing naval gun fire control systems. To implement this integration function, the signal processing methods of the existing IFF equipment were analyzed, and based on this, the integration function was implemented in a signal converter module. This paper is expected to serve as an important resource for future performance upgrades of internal equipment in aged naval ships.

The primary focus in the nuclear power market revolves around the advancement of small modular reactors (SMRs) featuring fourth-generation nuclear technology. Microreactors, a subset of SMRs, are characterized by their portability due to their very small size. Despite the accelerated development of microreactors, there are currently no regulations concerning their transportation. To pave the way for future regulatory requirements, existing laws and standards were initially examined. This included a review of basic standards, special conditions of the Road Traffic Act, road transport regulations for nuclear material shipments, and physical protection regulations. Additionally, summaries were provided for design standards related to acceleration loads and vibration tests during road transport and land-based nuclear power plant designs. The anticipated outcome of this study is comprehensive coverage of considerations for designing a transport system for micro-nuclear reactors, providing developers the flexibility to selectively apply them to their specific needs. Furthermore, it is anticipated that this information can serve as fundamental data for establishing licensing requirements in the future.

In the summer of 2018, the Korea-Japan (KJ) region experienced an extremely severe and prolonged heatwave. This study examines the GloSea6 model's prediction performance for the 2018 KJ heatwave event and investigates how its prediction skill is related to large-scale circulation patterns identified by the k-means clustering method. Cluster 1 pattern is characterized by a KJ high-pressure anomaly, Cluster 2 pattern is distinguished by an Eastern European highpressure anomaly, and Cluster 3 pattern is associated with a Pacific-Japan pattern-like anomaly. By analyzing the spatial correlation coefficients between these three identified circulation patterns and GloSea6 predictions, we assessed the contribution of each circulation pattern to the heatwave lifecycle. Our results show that the Eastern European highpressure pattern, in particular, plays a significant role in predicting the evolution of the development and peak phases of the 2018 KJ heatwave approximately two weeks in advance. Furthermore, this study suggests that an accurate representation of large-scale atmospheric circulations in upstream regions is a key factor in seasonal forecast models for improving the predictability of extreme weather events, such as the 2018 KJ heatwave.

The prolonged and heavy East Asian summer precipitation in 2020 may have been caused by an enhanced Madden-Julian Oscillation (MJO), which requires evaluation using forecast models. We examined the performance of GloSea6, an operational forecast model, in predicting the East Asian summer precipitation during July 2020, and investigated the role of MJO in the extreme rainfall event. Two experiments, CON and EXP, were conducted using different convection schemes, 6A and 5A, respectively to simulate various aspects of MJO. The EXP runs yielded stronger forecasts of East Asian precipitation for July 2020 than the CON runs, probably due to the prominent MJO realization in the former experiment. The stronger MJO created stronger moist southerly winds associated with the western North Pacific subtropical high, which led to increased precipitation. The strengthening of the MJO was found to improve the prediction accuracy of East Asian summer precipitation. However, it is important to note that this study does not discuss the impact of changes in the convection scheme on the modulation of MJO. Further research is needed to understand other factors that could strengthen the MJO and improve the forecast.

본 연구는 Yorkshire종, Landrace종 및 Duroc종에 대한 유전체자료를 이용하여 수퇘지의 웅취를 유발하는 세 가지 호르몬인 androstenone, indole 및 skatole 호르몬에 대한 유의적인 유전자영역, SNP 마커 및 후보유전자를 발굴하여 최종적으로 저웅취 종돈을 육종하는데 그 목적이 있다. Genomoe-Wide Association Study를 수행하기 위한 참조집단으로 수집한 유전체 정보는 Yorkshire, Landrace 및 Duroc종에서 각각 3,858 두, 472두 및 1,029두로 총 5,359두에 대한 유전체자료를 분석에 이용하였다. 추정되는 육종가의 정확도를 평가하기 위하여 REML방법을 ASREML 4.1 소프트웨어를 이용하여 분석하였고 세 가지 호르몬에 대하여 다형질 개체모형을 적용하였으며 추정된 육종가로부터 산출한 deregreessed DEBVincPA를 반응변수로 이용하여 연구를 수행하였다. 세 가지 호르몬에 대하여 BayesB와 C의 방법론을 통하여 분석한 결과 BayesB에서 세 가지 호르몬과 연관될 것으로 예상되는 SNP marker 9개, 즉 androstenone에서 3개, indole에서 1개 및 skatole에서 5개가 발굴되었다. BayesC에 서는 이보다 적은 SNP marker 3개가 발굴되었다. 수퇘지의 웅취 호르몬에 영향을 미칠 것으로 예상되는 후보유전자는 총 6개로 각각 LMAN2L, ABLI, NRG3, CDH12, TRAPPC9, MAN1A2로 나타났다

In this study, the machine learning which has been widely used in prediction algorithms recently was used. the research point was the CD(chudong) point which was a representative point of Daecheong Lake. Chlorophyll-a(Chl-a) concentration was used as a target variable for algae prediction. to predict the Chl-a concentration, a data set of water quality and quantity factors was consisted. we performed algorithms about random forest and gradient boosting with Python. to perform the algorithms, at first the correlation analysis between Chl-a and water quality and quantity data was studied. we extracted ten factors of high importance for water quality and quantity data. as a result of the algorithm performance index, the gradient boosting showed that RMSE was 2.72 mg/m³ and MSE was 7.40 mg/m³ and R² was 0.66. as a result of the residual analysis, the analysis result of gradient boosting was excellent. as a result of the algorithm execution, the gradient boosting algorithm was excellent. the gradient boosting algorithm was also excellent with 2.44 mg/m³ of RMSE in the machine learning hyperparameter adjustment result.

본 연구는 최근 해양사고가 점차 증가하고 있는 10톤 미만 소형어선의 규칙파 중 운동응답 특성에 대하여 수치해석을 통하여 분석하였다. 10톤 미만의 소형선박들을 크기별로 구분하여 해양사고 분석에 이용되고 있기 때문에 본 연구에서도 서로 다른 크기의 소형 어선 3척을 대상으로 운동응답 해석을 이행하였다. 선수파인 경우 장파장 영역에서 속력이 높아질수록 상하동요 및 종동요 응답도 커지고 있는 현상을 확인하였다. 가장 작은 3톤급 어선의 운동응답이 다른 크기의 어선보다 더 크게 나타나는 특성을 보여주었다. 선수사파 상태에서의 횡동요 운동은, 선박의 크기와 관계없이 점차 속력이 높아질수록 운동응답의 최대값이 장파장 영역으로 이동되는 특성을 확인할 수 있었다. 선수사파와 횡파에서 3척의 소형어선 모두 속력이 가장 높은 15노트에서 횡동요 운동이 가장 크게 나타나는 것을 알 수 있었다. 선수파 및 선수사파를 받으면서 항행할 경우 속력을 낮추는 것이 종운동과 횡운동 영향을 감소시킬수 있는 방법이라고 보여진다. 횡파에 의한 횡동요는 속력 및 선박의 크기와 관계없이 특정 파장에서만 급격히 커지는 경향을 보여 주었다. 전진속력이 있을 경우 선수 사파에 비해서 선미사파에서의 확연한 횡동요 감소 현상을 확인할 수 있었다. 선박의 크기 및 속력에 따라 선체운동응답의 최대값이 나타나는 특정 영역이 있으므로 이 운동 영향을 최소화 시킬 수 있는 운항방법이 고려되어 실행되어야 한다.

본 연구는 제주지역에서 사육되고 있는 제주 재래돼지기반의 제주흑돈(제주재래돼지 합성돈)에 대하여 산육형질인 등지방 두께, 일당증체량, 90 kg 도달일령에 대한 후보유전자 탐색을 위해 전장유전체 분석을 실시하였고, 유전체 육종가의 정확도 비교를 위해 베이지안 방법(BayesB, BayesC), π(0.00, 0.50, 0.90, 0.99)값과 개체 자신과 후대의 정보만 포함하고 조상의 정보에 대해 정보를 보정한 DEBVexcPA (Deregressed EBV exlude parents average)와 부모 평균을 포함한 DEBVincPA (Deregressed EBV include parents average)의 반응변수를 이용하였다. 산육형질에 대한 전장유전체 분석을 실시한 결과 등지방두께는 KIAA1549 유전자(SSC18 at 11Mb region), 일당증체량과 90 kg 도달일령에서 POLD3(SSC9 at 9Mb region), STX6(SSC9 at 134Mb region) 유전자가 공통적으로 탐색되었다. 유전체의 정확도 범위는 일당증체량 BayesB의 경우 DEBVexcPA와 DEBVincPA에서 각각 0.285~0.305와 0.497~0.510과 BayesC에서 0.287~0.296와 0.499~0.511으로 추정되었다. 90 kg 도달일령은 BayesB에서 DEBVexcPA와 DEBVincPA는 각각 0.284~0.305와 0.497~0.510, BayesC에서는 0.284~0.296와 0.498-0.511로 추정되었다. 특히, 등지방두께의 유전체 정확도가 BayesB방법론의 DEBVincPA에서 0.625로 가장 높게 추정되었다. 제주흑돈의 산육형질에 대한 유전적인 개량 속도를 가속화하기 위해 유전체 선발법을 적용하는데 있어 부모 평균을 포함한 DEBVincPA (Deregressed EBV include parents average)의 반응변수를 이용하는 것이 바람직하다고 판단된다.

The decrease in under keel clearance (UKC) due to the increase of draft that occurs during advancing and turning of very large vessels of different types was analyzed based on computational fluid dynamics (CFD). The trim change in the Duisburg test case (DTC) container ship was much smaller than that of the KRISO very large crude oil carrier 2 (KVLCC2). The sinkage of both ships increased gradually as the water depth became shallower. The amount of sinkage change in DTC was greater than that in KVLCC2. The maximum heel angle was much larger for DTC than for KVLCC2. Both ships showed outward heel angles up to medium-deep water. However, when the water depth became shallow, an inward heel was generated by the shallow water effect. The inward heel increased rapidly in very shallow water. For DTC, the reduction ratio was very large at very shallow water. DTC appeared to be larger than KVLCC2 in terms of the decreased UKC because of shallow water in advancing and turning. In this study, a new result was derived showing that a ship turning in a steady state due to the influence of shallow water can incline inward, which is the turning direction.

The change in the open porosity of bulk graphite as a function of the uniaxial molding pressure during manufacturing is studied using artificial graphite powder. Subsequently, the graphite is impregnated to determine the effect of the open porosity on the impregnation efficiency and to improve the density of the final bulk graphite. Bulk graphite is manufactured with different uniaxial molding pressures after mixing graphite powder, which is the by-product of processing the final graphite products and phenolic resin. The bulk density and open porosity are measured using the Archimedes method. The bulk density and open porosity of bulk graphite increase as the molding pressure increases. The open porosity of molded bulk graphite is 25.35% at 30 MPa and 29.84% at 300 MPa. It is confirmed that the impregnation efficiency increases when the impregnation process is performed on a specimen with large open porosity. In this study, the bulk density of bulk graphite molded at 300 MPa is 11.06% higher than that before impregnation, which is the highest reported increase. Therefore, it is expected that the higher the uniaxial pressure, the higher the density of bulk graphite.

In the manufacturing of bulk graphite, pores produced by vaporization and discharge of volatile materials in binders during carbonization reduce the density of bulk graphite, which adversely affects the electrical conductivity, strength and mechanical properties. Therefore, an impregnation process is introduced to fill the pores and increase the density of bulk graphite. In this study, bulk graphite is prepared by varying the viscosity of the impregnant. The microstructure of bulk graphite is observed. The flexural strength and electrical resistivity are measured. As the viscosity of the impregnants decreases and the number of impregnations increases, it is shown that the number of pores decreases. The density before impregnation is 1.62 g/cm3. The density increases to 1.67 g/cm3 and porosity decreases by 18.6 % after three impregnations using 5.1 cP impregnant, resulting in the best pore-filling effect. After three times of impregnation with a viscosity of 5.1 cP, the flexural strength increases by 55.2 % and the electrical resistivity decreases by 86.76 %. This shows that a slight increase in density due to the pore-filling effect improves the properties of bulk graphite.

Pores produced by carbonization in bulk graphite process degrade the mechanical and electrical properties of bulk graphite. Therefore, the pores of bulk graphite must be reduced and an impregnation process needs to be performed for this reason. In this study, bulk graphite is impregnated by varying the viscosity of the impregnant. The pore volume and pore size distribution, according to the viscosity of the impregnant, are analyzed using a porosimeter. The total pore volume of bulk graphite is analyzed from the cumulative amount of mercury penetrated. The volume for a specific pore size is interpreted as the amount of mercury penetrating into that pore size. This decreases the cumulative amount of mercury penetrating into the recarbonized bulk graphite after impregnation because the viscosity of the impregnant is lower. The cumulative amount of mercury penetrating into bulk graphite before impregnation and after three times of impregnation with 5.1cP are 0.144 mL/g and 0.125 mL/gm, respectively. Therefore, it is confirmed that the impregnant filled the pores of the bulk graphite well. In this study, the impregnant with 5.1 cP, which is the lowest viscosity, shows the best effect for reducing the total pore volume. In addition, it is confirmed by Raman analysis that the impregnant is filled inside the pores. It is confirmed that phenolic resin, the impregnant, exists inside the pores through micro-Raman analysis from the inside of the pore to the outside.

Conductive polymer composites with high electrical and mechanical properties are in demand for bipolar plates of phosphoric acid fuel cells (PAFC). In this study, composites based on natural graphite/fluorinated ethylene propylene (FEP) and different ratios of carbon black are mixed and hot formed into bars. The overall content of natural graphite is replaced by carbon black (0.2 wt% to 3.0 wt%). It is found that the addition of carbon black reduces electrical resistivity and density. The density of composite materials added with carbon black 3.0 wt% is 2.168 g/cm3, which is 0.017 g/cm3 less than that of non-additive composites. In-plane electrical resistivity is 7.68 μΩm and through-plane electrical resistivity is 27.66 μΩm. Compared with non-additive composites, in-plane electrical resistivity decreases by 95.7 % and through-plane decreases by 95.9 %. Also, the bending strength is about 30 % improved when carbon black is added at 2.0 wt% compared to non-additive cases. The decrease of electrical resistivity of composites is estimated to stem from the carbon black, which is a conductive material located between melted FEP and acts a path for electrons; the increasing mechanical properties are estimated to result from carbon black filling up pores in the composites.

In this study, we performed algorithms to predict algae of Chlorophyll-a (Chl-a). Water quality and quantity data of the middle Nakdong River area were used. At first, the correlation analysis between Chl-a and water quality and quantity data was studied. We extracted ten factors of high importance for water quality and quantity data about the two weirs. Algorithms predicted how ten factors affected Chl-a occurrence. We performed algorithms about decision tree, random forest, elastic net, gradient boosting with Python. The root mean square error (RMSE) value was used to evaluate excellent algorithms. The gradient boosting showed 10.55 of RMSE value for the Gangjeonggoryeong (GG) site and 11.43 of RMSE value for the Dalsung (DS) site. The gradient boosting algorithm showed excellent results for GG and DS sites. Prediction value for the four algorithms was also evaluated through the Receiver operating characteristic (ROC) curve and Area under curve (AUC). As a result of the evaluation, the AUC value was 0.877 at GG site and the AUC value was 0.951 at DS site. So the algorithm‘s ability to interpret seemed to be excellent.

본 연구는 제주에서 사육되고 있는 제주흑돈(제주 제래돼지 합성돈)에서 생산형질인 등지방두께, 일당증체량, 90kg도달일령과 번식형질인 총산자 수 및 생존산자수를 조사하고, 이에 대한 상가적효과와 모체환경효과를 통한 분산성분 및 유전모수를 추정하여 유전적 개량에 필요한 기초 자료를 위해 분석을 진행하였다. 생산형질 내에서 등지방두께, 일당증체량 및 90kg도달일령에 대하여 추정된 유전력은 각각 0.364, 0.271 및 0.300으로 추정되었으며, 번식형질 내에서 총산자수와 생존산자수에 대하여 추정된 유전력은 각각 0.072, 및 0.076로 유전력을 갖는 것으로 추정되었다. 생산형질에서 모체의 유전분산과 모체 공통 환경분산은 각각 0.019-0.385과 0.034-0.357로 추정되었으며, 번식형질의 경우 모체공통 환경분산은 0.348-0.459 로 추정되었다. 따라서, 제주흑돈에 대한 유전모수 추정 시 개체의 직접적인 유전효과 뿐만 아니라, 모체의 유전 또는 공통 환경효과를 고려해야 유전모수 등이 과대 추정 (over-estimate) 되는 현상을 방지 할 수 있으며, 개체들에 대한 정확한 유전 능력 평가가 이루어질 것으로 사료된다.

웅취는 돼지고기의 이취로서 소비자의 소비성에 부정적인 영향을 미친다. 웅취는 거세를 하지 않은 수퇘지의 지방조직에 안드로스테 논, 스카톨 및 인돌과 같은 호르몬의 축적으로 인한 것이다. 본 연구는 웅취에 영향을 미치는 호르몬과 성장 및 번식 형질간의 유전상관도 를 추정하고 동물복지측면에서 웅취 호르몬이 낮은 수퇘지를 개발하기 위해 수행되었다. 본 연구를 위하여 3개 품종, Duroc, Landrace, Yorskhire 517두를 공시돈으로 수행하였다. 웅취 호르몬 분석을 위한 샘플채취는 수퇘지의 목부위 지방을 바이옵시 방식으로 채취하여 각 품종별 안드로스테논, 스카톨 및 인돌을 분석하였다. 안드로스테논 분석 결과, Duroc 품종이 1.684 ug/g으로 가장 높았고, 타 품종은 0.875-0.920 ug/g으로 상대적으로 낮았다. 스카톨의 농도는 Yorskhire가 0.095 ug/g으로 가장 높았고 인돌은 Duroc이 0.058 ug/g으로 가장 높았다. 품종과 개체에 따라서 3종류 웅취 호르몬의 농도 차이는 매우 컸다. 안드로스테논, 스카톨 및 인돌의 유전력은 0.40, 0.17 및 0.01으로, 안드로스테논의 유전력이 가장 높았다. 웅취 호르몬 농도와 다른 경제 형질(성장 및 번식 형질) 사이의 유전적 상관관계를 조사하였으나, 웅취 농도와의 상관관계는 매우 낮았다. 웅취 호르몬의 농도가 유전력도 높고 개체별 차이가 크고 다른 경제 형질과의 유전적 상관도가 낮기 때문에, 육종을 통한 저 웅취 부계 종돈 작출이 가능할 것으로 판단된다.