This study aims to refine the existing shear strength model for reinforced concrete(RC) beam–column connections by explicitly incorporating the bi-directional loading effect, which more accurately reflects the actual loading conditions of RC structures during earthquakes. A new database consisting of 21 RC beam–column connection specimens tested under simultaneous bi-directional loading was collected and analyzed to investigate the influence of key parameters on joint shear strength. The results revealed that the joint configuration and the presence of a slab are the primary factors governing the extent of bi-directional loading effect on joint shear strength. Based on these findings, a set of simple and practical modification factors was proposed to refine the existing joint shear strength model to account for bi-directional loading effect. The outcomes of this study provide a rational basis for incorporating bi-directional loading effect into the shear strength evaluation of RC beam–column connections

본 논문에서는 상반회전 추진 프로펠러 이중축계의 회전 동특성을 정밀하게 분석하기 위한 수치해석 방법을 제안하였다. 제안된 해석 기법은 티모쉔코 보 이론 기반의 유한요소법을 이용하여 자이로스코픽 효과와 베어링 감쇠를 포함한 운동방정식을 정식화하였 다. 개발된 해석 코드는 기존 동축 회전체 모델과의 비교를 통해 검증되었으며, 고유진동수와 캠벨선도 결과가 매우 잘 일치함을 확인 하였다. CRP 축계의 시뮬레이션 결과 1차 공진모드에서 내축의 변위가 외축보다 커 축간 충돌 가능성이 높은 것으로 나타났다. 베어 링 강성 증가 시 고유진동수가 상승하여 공진영역을 회피할 수 있었으며, 축 직경 변화는 상대적으로 영향이 작았다. 제안된 해석 기 법은 상반회전 추진 이중축계의 설계 평가 및 진동 안정성 분석에 유용하게 활용될 수 있으며, 향후에는 비선형 베어링 특성 및 유체– 구조 연성효과를 포함한 확장 연구로 발전시킬 수 있을 것이다.

Explosive Ordnance Disposal (EOD) robots are essential for safeguarding operators and reducing risks in high-threat environments. This study reviews international cases and current technologies to identify limitations and propose improvement strategies. Mission success depends on four core domains: mobility, power, manipulator precision, and communication. Current tracked and wheeled platforms lack self-righting, leading to research on flippers, wheel–leg hybrids, and quadrupedal locomotion. Battery reliance remains critical; short-term solutions include intelligent Battery Management Systems (BMS) and battery-exchange robots, while long-term progress requires high-density energy sources. Manipulator performance is hindered by inertia and backlash, but precision actuators, soft grippers, and sensor fusion with AI can enhance dexterity. Communication faces losses and jamming, requiring multilayered resilience with Software-Defined Radio (SDR), cognitive radio, relay nodes, and hybrid links. By mapping improvements to Technology Readiness Levels (TRL), this study suggests a phased roadmap where mature technologies address immediate needs, while AI-driven autonomy and secure networks define long-term advances.

This study was conducted to provide comprehensive information on the current status, constraints, and policy responses regarding rice cultivation in Uzbekistan for researchers and policymakers engaged in rice production in Central Asia. Despite annual fluctuations, Uzbekistan’s rice cultivation area has consistently exceeded 100,000 hectares each year. The yield per unit area improved by 19.2%, increasing from 4.21 t/ha in 2021 to 5.02 t/ha in 2024. In terms of cultivation methods, the proportion of doub le c ropping rose f rom 50.7% t o 71.6%, a lthough productivity remained h igher in s ingle cropping (5.35 t/ha) compared to double cropping (4.88 t/ha). Rice demonstrated an economic advantage of 2-5 times per hectare compared to major crops such as wheat, corn, and cotton. However, domestic production growth has not kept pace with rising consumption demands, leading to a sharp increase in imports, from 9,000 tons in 2019 to 108,800 tons in 2023. The structure of rice imports is shifting from a heavy reliance on Kazakhstan (90%) toward diversification, including partnerships with Pakistan, Thailand, and other countries. Major constraints to rice production in Uzbekistan include an arid climate, chronic irrigation water shortages, and soil salinization, which affects 50-70% of irrigated farmland. In response, the government established a comprehensive development strategy through Cabinet Resolution No. 986 in 2019 and is currently promoting economies of scale by establishing 42 clusters across 8 provinces (covering 41,440 hectares, or 29.7% of the total area). To address water scarcity, laser land leveling technology has been implemented on over 700,000 hectares as of 2024, aimed at reducing irrigation water usage and increasing yields, with plans to further expand water-saving cultivation technologies. In terms of international cooperation, the KOPIA project is enhancing quality seed production and distribution, as well as establishing machine transplanting cultivation technology. Partnerships with IRRI and participation in the Council for Partnership on Rice Research in Asia (CORRA) are strengthening the development of climate- adaptive varieties and international networks. Overall, Uzbekistan’s rice industry has the strategic potential to contribute significantly to food security, rural economic development, and regional trade activation through systematic policy implementation and enhanced international cooperation.

This study was served as a foundational investigation about Cook-off phenomenon of a 7.62mm caliber machine gun. In this paper, the Cook-off phenomenon was described and the test precedure developed with reference to TOP 3-2-045 was introduced along with the test firearm. Through live-fire tests conducted according to the test procedure, changes in barrel temperature based on the number of rounds fired, as well as the peak temperature, were observed. The occurrence, time and temperature of cook-off were also identified. Lastly, an analysis of the derived test results was conducted, and the limitations of this study were discussed along with suggestions for future studies.

This study proposes a steel plate retrofit method and a polyurea method to improve the structural stability and usability of a factory floor slab with a thickness of 120mm. To assess vibration changes, vibrations were measured before and after retrofit. A numerical analysis model was also developed to evaluate improvements in structural safety and usability. The natural frequency increased from 11.4Hz to 17Hz through steel plate reinforcement, confirming an increase in slab stiffness. The damping ratio increased from 2.3% to 3.2% with polyurea reinforcement, indicating improved vibration reduction. Additionally, numerical analysis modeling showed that the natural frequency increased from 13.9Hz to 16.2Hz due to the steel plate reinforcement, enhancing the dynamic characteristics of the floor slab and confirming the reliability of the analysis model.

우리나라 헌법 제107조 제3항은 재판의 전심절차로서 행정심판을 할 수 있 으며 절차는 법률로 정하되, 사법절차가 준용되어야 한다고 규정한다. 그리고 행정심판법 제4조 제1항에서는 사안의 전문성과 특수성이 인정되면 필요에 따 라 개별법이 정한 특례절차에 따라 심판을 할 수 있도록 규정하고 있다. 이러 한 특례절차에 따른 행정심판을 특별행정심판이라 하는데, 해양안전심판, 특허 심판 및 조세심판 등이 있다. 특별행정심판 중에서도 해양안전심판은 해양사고의 원인규명재결뿐만 아니 라 해기사 등에 대한 징계재결까지도 심판의 결과로 도출하는 특별한 형태의 행정심판으로서 구술변론주의, 대심주의 및 조사관의 청구독점주의 등을 채택 하고 있다. 그러나 조사관은 해양사고관련자를 조사하는 권한을 가지고 있어 해양사고관련자와 대등한 입장이라 보기 어렵다. 그러므로 상대적 약자인 해양 사고관련자의 정당한 권리구제와 방어권을 보장하기 위해서는 심판변론인 제 도의 적극적 활용이 무엇보다 중요하다. 이 연구에서는 해양사고심판의 심판변론인제도를 다양한 측면에서 살펴보 고, 다른 특별행정심판인 특허심판과 조세심판 제도와 비교·분석하여 해양안전 심판의 심판변론인제도에 대한 문제점을 도출하고 개선방안을 제안하고자 한다.

This study is about the evaluation for shock-proof performance of the system, elastically support the low accumulator of the naval artillery against underwater explosion, using DDAM. For the evaluation, the shock analysis procedure using DDAM, supported by MSC/NASTRAN, was briefly described. In addition, in order to perform the shock analysis, the elastic support system was modeled as a finite element. The shock analysis of the elastic support system was performed by selecting the analysis frequency range so that reliable results can be obtained. Finally, the shock-proof performance of the system was evaluated by comparing the shock analysis results with the properties of the elastic support system.

This study is about the design of an elastic support system to isolate the structural noise of the low accumulator of the naval artillery among the equipment mounted on a warship. As the structural noise measurement value of the low accumulator transmitted to the ship exceeded the standard value, a method of applying an elastic mount between the equipment and the ship was devised to isolate the structural noise. By calculating the target vibration isolation efficiency, the vibration isolating system was designed in consideration of design factors such as the system's natural frequency and static displacement. Finally, the performance of the structural noise reduction of the designed vibration isolating system was verified by evaluating the structural noise transmitted to the foundation plate of the equipment from the low accumulator to which designed elastic support system was applied.

Recently, a closed-type plant factory has been receiving attention as a advanced agricultural method. It has diverse advantages such as climate-independence, high productivity and stable year-round production. However, high energy cost caused by environmental control system is considered as a challenges of a closed-type plant factory. In order to reduce the energy cost, investigation about energy load which is directly connected to energy consumption needs to be conducted. In this study, energy load changes of a plant factory have been analytically analyzed according to the environmental changes. The target plant factory was a lettuce growing container farm. Firstly, the impact of photoperiod, set temperature and relative humidity change were examined. Under the climate condition of Daejeon in South Korea, increase of photoperiod and set temperature rose a yearly energy demand of a container farm. However, increase of set relative humidity decreased a yearly energy demand. Secondly, the climate environment effect was compared by investigating the energy demand under 9 different climate conditions. As a result, the difference between maximum and minimum value of the yearly energy demand showed 21.7%. Lastly, sensitivity analysis of each parameter (photoperiod, set temperature and relative humidity) has been suggested under 3 different climate conditions. The ratio of heating and cooling demand was varied depending on the climate, so the effect of each parameter became different.

Cyanobacteria Pseudanabaena strains are known to produce 2-MIB (odorous material) in freshwater systems, thereby causing problems in water use. However, their physiological responses to environmental factors in relation with 2-MIB production is not well explored. This study was conducted to evaluate the effect of temperature on the growth and 2-MIB production of Pseudanabaena redekei. The experimental cyanobacteria strains were separated from the Uiam Reservoir (North Han River) and cultured in the BG-11 medium. Temperature was set to 10, 15, 20, 25, and 30℃ for the experiment, in the reflection of the seasonal water temperature variation in situ. For each temperature treatment, cyanobacterial biomass (Chl-a) and 2-MIB concentration (intra-cellular and extra-cellular fractions) were measured every 2 days for 18 days. Both maximal growth and total 2-MIB production of P. redekei appeared at 30℃. While intra-cellular 2-MIB contents were similar (26~29 ng L-1) regardless of treated temperatures, extra-cellular 2-MIB concentration was higher only in high temperature conditions (25~30℃), indicating that the extents of 2-MIB biosynthesis and release by P. redekei vary with temperature. The 2-MIB productivity of P. redekei was much higher in low-temperature conditions (10~15℃) than high temperature conditions (25~30℃). This study demonstrated that temperature was a critical factor contributing to 2-MIB biosynthesis and its release in cell growth (r=0.605, p<0.01). These results are important to understand the dynamics of 2-MIB in the field and thereby provide basic information for managing odorous material in drinking water resources.

The clear-water phase (CWP) is a notable limnological phenomenon in freshwater systems caused by predatory interactions between large filter-feeding zooplankton and phytoplankton. However, the mechanisms and factors that influence the extent of CWP, particularly in complex water systems with both fluvial and lacustrine characteristics, remain poorly understood. The present study evaluated CWP occurrence patterns at different sites in a large reservoir located in a temperate monsoon region (Lake Paldang, Korea); the relationships among factors associated with CWP occurrence, such as transparency, zooplankton diversity, and chlorophyll a concentration were investigated. Transparency exhibited significant correlations with precipitation and retention time, as well as the relative abundance of zooplankton (p<0.01), suggesting that a change in the retention time due to precipitation can alter CWP. Data collected before and after CWP occurrence were analyzed using paired t-test to determine variations in CWP occurrence based on the water system characteristics. The results demonstrated that various factors were associated with CWP occurrence in the fluvial-type and lacustrine-type sites. The correlation between zooplankton biomass and transparency was stronger in the lacustrine-type sites than in the fluvial-type sites. The lacustrine-type sites, where cladoceran emergence is common and is associated with long retention times, favored CWP occurrence. The results suggest that lacustrine-type sites, which are conducive to zooplankton development and have relatively long retention times, enhance CWP occurrence. Furthermore, CWP occurrence was notable in spring, and the present study revealed that site-specific CWP could occur throughout the year, regardless of the season.

This study develops a new device system for measuring a slope of object with non-adhesive, non-contact and non-face-to-face, namely Inclinometer Slope Laser Measuring (ISLM), that is applicable in the field. This system includes cradle, laser, camera, and computer and the filming and is performed after laser projection at programmed intervals. After measuring the amount of displacement converted to numerical values, these values can then be transferred to the office using the selected data transmission method. The obtained results from the test carried out to verify the reliability of the ISLM system indicated that the ISLM system can measure with accurately level of 0.1mm/Pixel at 1m distance and when increasing the camera resolution, the precision might increase proportionally. Therefore, the proposed measure system may widely apply on-site for various constructions, especially, in the case of object with very high surface temperature where exhibits difficulty to directly measure the adjacent structures. However, due to the sensitive reaction to the illuminance, this method can be applied with caution at times of large changes in illuminance, such as at dawn and at dusk.

Many Korean domestic masonry structures constructed since 1970 have been found to be vulnerable to earthquakes because they lack efficient lateral force resistance. Many studies have shown that the brick and mortar suddenly experience brittle fracture and out-of-plane collapse when they reach the inelastic range. This study evaluated the seismic retrofitting of non-reinforced masonry with Hybrid Super Coating (HSC) and Cast, manufactured using glass fiber. Four types of specimen original specimen (BR-OR), one layered HSC (BR-HS-O), two-layered HSC (BR-HS-B), one layered HSC, and Cast (BR-CT-HS-O) were constructed and analyzed using compression, flexural tensile, diagonal compression, and triplet tests. The specimen responses were presented and discussed in load-displacement curves, maximum strength, and crack propagation. The compressive strength of the retrofit specimens slightly increased, while the flexural tensile strength of the retrofit specimens increased significantly. In addition, the HSC and Cast also produced a considerable increase in the ductile response of specimens before failure. Diagonal compression test results showed that HSC delayed brittle cracks between the mortar and bricks and resulted in larger displacement before failure than the original brick. The triplet test results confirmed that the bonding strength of the retrofit specimens also increased. The application of HSC and Cast was found to restrain the occurrence of brittle failure effectively and delayed the collapse of masonry wall structures.