• Journal of Ocean Engineering and Technology
• /
• v.38 no.1
• /
• pp.30-42
• /
• 2024

This study examined the jack-up spudcan penetration for a new type of offshore wind substructure newly proposed using the jack-up concept to reduce construction costs. The jack-up spudcan for offshore wind turbines should be designed to penetrate a stable soil layer capable of supporting operational loads. This study evaluated multi-layered soil conditions using centrifuge tests: loose sand over clay and loose sand-clay-dense sand. The penetration resistance profiles of spudcan recorded at the centrifuge tests were compared with the ISO and InSafeJIP methods. In the tests, a spudcan punch-through effect slightly emerged under the sand-over-clay condition, and a spudcan squeezing effect occurred in the clay-over-sand layer. On the other hand, these two effects were not critically predicted using the ISO method, and the InSafeJIP result predicted only punch-through failure. Nevertheless, ISO and InSafeJIP methods were well-matched under the conditions of the clay layer beneath the sand and the penetration resistance profiles at the clay layer of centrifuge tests. Therefore, the ISO and InSafeJIP methods well predict the punch-through effect at the clay layer but have limitations for penetration resistance predictions at shallow depths and strong stratum soil below a weak layer.

• International journal of advanced smart convergence
• /
• v.13 no.1
• /
• pp.162-179
• /
• 2024

With the acceleration of China's urbanization process, the economic development and market potential of small and medium-sized cities have been constantly enhanced, with the urbanization competition having been caught in the vortex of homogenization. However, small and medium-sized cities are exposed to limited resources and funds, and therefore need to be more flexible and innovative in the strategy implementation, while urban brand communication is one of the key factors to promote the competitiveness of cities. Taking the small and medium-sized cities in China as the research objects, this study, based on the domestic and foreign theories about the brand communication of small and medium-sized cities, as well as other city-related theories, analyzes textual materials about the current situation and new changes in brand communication of small and medium-sized cities with grounded theory, reflecting on the problems in brand communication in China's small and medium-sized cities. Combining the basic elements of urban brand communication, a model for constructing brand communication strategies for small and medium-sized cities is further proposed, so as to provide the differentiated and distinctive strategies for the construction and communication of urban brands in small and medium-sized cities in China, as well as provide a new perspective and strategy on how to enhance the competitiveness and contribute to the sustainable economic development of small and medium-sized.

• Smart Structures and Systems
• /
• v.6 no.5_6
• /
• pp.481-504
• /
• 2010

Wireless smart sensor networks (WSSNs) have been proposed by a number of researchers to evaluate the current condition of civil infrastructure, offering improved understanding of dynamic response through dense instrumentation. As focus moves from laboratory testing to full-scale implementation, the need for multi-hop communication to address issues associated with the large size of civil infrastructure and their limited radio power has become apparent. Multi-hop communication protocols allow sensors to cooperate to reliably deliver data between nodes outside of direct communication range. However, application specific requirements, such as high sampling rates, vast amounts of data to be collected, precise internodal synchronization, and reliable communication, are quite challenging to achieve with generic multi-hop communication protocols. This paper proposes two complementary reliable multi-hop communication solutions for monitoring of civil infrastructure. In the first approach, termed herein General Purpose Multi-hop (GPMH), the wide variety of communication patterns involved in structural health monitoring, particularly in decentralized implementations, are acknowledged to develop a flexible and adaptable any-to-any communication protocol. In the second approach, termed herein Single-Sink Multi-hop (SSMH), an efficient many-to-one protocol utilizing all available RF channels is designed to minimize the time required to collect the large amounts of data generated by dense arrays of sensor nodes. Both protocols adopt the Ad-hoc On-demand Distance Vector (AODV) routing protocol, which provides any-to-any routing and multi-cast capability, and supports a broad range of communication patterns. The proposed implementations refine the routing metric by considering the stability of links, exclude functionality unnecessary in mostly-static WSSNs, and integrate a reliable communication layer with the AODV protocol. These customizations have resulted in robust realizations of multi-hop reliable communication that meet the demands of structural health monitoring.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
• /
• v.34 no.2
• /
• pp.207-215
• /
• 2016

The demand for spatial data service technologies is increasing lately with the development of realistic 3D spatial information services and ICT (Information and Communication Technology). Research is being conducted on the real-time provision of spatial data services through a variety of mobile and Web-based contents. Big data or cloud computing can be presented as alternatives to the construction of spatial data for the effective use of large volumes of data. In this paper, the process of building HLM (Hyper Live Map) using multi-source data to acquire stereo CCTV and other various data is presented and a big data service architecture design is proposed for the use of flexible and scalable cloud computing to handle big data created by users through such media as social network services and black boxes. The provision of spatial data services in real time using big data and cloud computing will enable us to implement navigation systems, vehicle augmented reality, real-time 3D spatial information, and single picture based positioning above the single GPS level using low-cost image-based position recognition technology in the future. Furthermore, Big Data and Cloud Computing are also used for data collection and provision in U-City and Smart-City environment as well, and the big data service architecture will provide users with information in real time.

• Tunnel and Underground Space
• /
• v.32 no.6
• /
• pp.558-567
• /
• 2022

The evolution of temperature and thermal stress in a granite specimen is studied via heating experiment in the context of a high-level radioactive waste repository. A heating condition based on the decay-induced heat is applied to a cubic granite specimen to measure the temperature and stress distributions and their evolution over time. The temperature increases quickly due to heat conduction along the heated surfaces, but a significant amount of thermal energy is also lost through other surfaces due to air convection and conduction into the loading machine. A three-dimensional finite element-based model is used to numerically reproduce the experiment, and the thermo-mechanical coupling behavior and modeling conditions are validated with the comparison to the experimental results. The most crucial factors influencing the heating experiment are analyzed and summarized in this paper for future works.

• Journal of Internet of Things and Convergence
• /
• v.8 no.3
• /
• pp.63-68
• /
• 2022

Due to COVID-19, many paradigm shifts in existing manufacturing facilities and the expansion of non-face-to-face services are accelerating worldwide. A representative technology is digital twin technology. Such digital twin technology, which existed only conceptually in the past, has recently become feasible with the construction of a 5G-based network. Accordingly, this paper designed and implemented a part of the USB process to enable digital twins based on OPC UA communication, which is a standard interlocking structure, between real object objects and virtual reality-based USB process in accordance with this paradigm change. By reflecting the physical characteristics of real objects together, it is possible to simulate real-time synchronization of these with real objects. In the future, this can be applied to various industrial fields, and it is expected that it will be possible to reduce costs for decision-making and prevent dangerous accidents.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2022.05a
• /
• pp.469-472
• /
• 2022

With the recent development of intelligent transportation systems, various technologies applying deep learning technology are being used. To crackdown on illegal vehicles and criminal vehicles driving on the road, a vehicle type classification system capable of accurately determining the type of vehicle is required. This study proposes a vehicle type classification system optimized for mobile traffic control systems using YOLO(You Only Look Once). The system uses a one-stage object detection algorithm YOLOv5 to detect vehicles into six classes: passenger cars, subcompact, compact, and midsize vans, full-size vans, trucks, motorcycles, special vehicles, and construction machinery. About 5,000 pieces of domestic vehicle image data built by the Korea Institute of Science and Technology for the development of artificial intelligence technology were used as learning data. It proposes a lane designation control system that applies a vehicle type classification algorithm capable of recognizing both front and side angles with one camera.

• Membrane and Water Treatment
• /
• v.14 no.4
• /
• pp.163-173
• /
• 2023

The presence of high amounts of organic and inorganic contaminants in textile wastewater is a major environmental concern. Therefore, the treatment of textile wastewater is an urgent issue to save the aquatic environment. The disposal of large quantities of untreated textile wastewater into inland water bodies can cause serious water pollution. In this study, synthetic dye wastewater samples were prepared using orange dye in the laboratory. The synthetic samples were then treated by a batch adsorption process using the prepared activated carbon (AC) from date pits. The wastewater parameters studied were the pH, total dissolved solids (TDS), total suspended solids (TSS), electrical conductivity (EC) and salinity. The activated adsorption process showed that the maximum removal efficiencies of electric conductivity (EC), salinity, TDS and TSS were 65%, 92%, 89% and 90%, respectively. The removal efficiencies were proportional to the increase in contact time (30-120 min) and AC adsorbent dose (1, 3 and 5 g/L). The adsorption profile indicates that 5 g/L of adsorbent delivers better results for TDS, EC, TSS and salinity at contact time of 120 min. The adsorption characteristics are better suited to the pseudo-second-order kinetic model than to the pseudo-first-order kinetic model. The Langmuir and Freundlich isotherms were well suited for describing the adsorption or contact behavior of EC and TSS within the studied system.

• 한국신재생에너지학회:학술대회논문집
• /
• 2010.11a
• /
• pp.140-140
• /
• 2010

최근 정부가 저탄소 녹색성장을 새로운 국정비전으로 제시하고 혁신적 그린에너지 기술개발을 위해 연평균 20%이상의 R&D 예산을 증액하고 있는 상황에서 연구개발결과의 상용화율 제고를 위한 연구기획, 평가, 관리시스템의 개선이 시급한 실정이다. 특히 선진국의 경우 최근 3년간 에너지분야 R&D의 상용화율이 미국 35.9%, 유럽 46.8%로서 24.2%인 한국에 비해 매우 높다고 할 수 있다. 이와같은 격차가 존재하는 것에 대해서 다양한 요인을 생각해볼 수 있겠지만, 크게 시장적인 또는 산업적인 측면에서의 중요도를 기준으로 연구과제를 선정하지 못하고 있다는 점과 연구개발결과를 효율적으로 사업화하고 있지 못하고 있다는 점을 생각해볼 수 있다. 특히 에너지 분야는 대규모 자금의 초기소요 및 개발기술 상용화기간의 장기화등으로 인해 사업화 실적이 타산업대비 매우 저조한 편이다. 이와같은 연구결과의 사업화와 관련된 문제점을 극복하기 위한 노력으로 국내에서 다양한 형태의 기술사업화 지원프로그램이 운영괴고 있으나, 에너지 분야에 특화된 프로그램은 부족한 상황이다. 반면에 미국의 경우, 재생에너지 R&D분야 전문투자자 그룹인 클린테크그룹 등을 중심으로 2002년부터 현재까지 다수의 녹색기술분야에 특화된 기술사업화 지원 프로그램을 운영하고 있다. 그 결과 현재까지 약 9년간 총 16억$의 투자유치에 성공함으로써 민간투자 활성화 역할을 담당하고 있다. 따라서 국내의 경우에도 이와같은 에너지 R&D 결과를 효과적으로 사업화로 연계시킬 수 있는 관련 프로그램 등이 시급히 도입되어야 할 것이다. 본 논문에서는 국내의 사업화 부진문제를 해결하기 위한 하나의 방안으로서 올해부터 정부주관으로 시행되고 있는 녹색인증사업을 활용하여 사업화가 유망한 기술 및 기업을 선별하고, 이에 대해 사업화 지원을 위한 후속프로그램을 적극 지원함으로써 연구개발결과의 경제적 활용도를 획기적으로 개선하는 방안을 제시하고자 한다. 또한 사업화 지원프로그램의 효율성을 높이기 위해 수도권, 영남권, 호남권 등 지역별 TP 등을 중심으로 기술사업화 협력 네트워크를 구축하고, 이를 기반으로 한 수요기술조사, 기술마케팅, 투자자유치 등의 관련프로그램을 개발하여 전단의 시스템과 융합시킴으로써 향후의 정부주도 R&D결과의 상용화율을 제고할 수 있는 시스템을 제안하고자 한다. 이에는 에너지 R&D분야별 기술적 시장적 특징분석, 지역별 산업특성과 기술공급 서플라이 체인분석을 토대로 한 기술이전 잠재수요기업 투자자를 대상으로 한 맞춤형 기술사업화 프로그램 등이 포함된다. 마지막으로 제안된 시스템에 대한 타당성 검증을 위해 올해년도에 시행한 녹색인증 기술사업화 연계프로그램 및 기술사업화 협력네트워크 활용사례 등을 분석하고, 향후 발전방향으로서 기술사업화 유관기관간간 기술사업화 정보교환 및 사업화 유망기술 기업 마케팅 등을 기본내용으로 한 시장지향적 녹색에너지 R&D 관리 시스템 구축방안을 제시하고자 한다.

• Journal of Drive and Control
• /
• v.20 no.4
• /
• pp.115-122
• /
• 2023

This study utilized a discrete element method (DEM) simulation, as one of the virtual field trials, to predict the impact of tillage depth on the rotary blade shaft during rotavator tilling. The virtual field for the simulation was generated according to soil properties observed in an actual field. Following the generation of particles for the virtual field, a sequence of calibration steps followed to align the mechanical properties more closely with those of real soil. Calibration was conducted with a focus on bulk density and shear torque, resulting in calibration errors of just 0.02% for bulk density and 0.52% for shear torque. The prediction of the load on a rotary tiller's blade shaft involved a three-pronged approach, considering shaft torque, draft force, and vertical force. In terms of shaft torque, the values exhibited significant increases of 42.34% and 36.91% for every 5-centimeter increment in tillage depth. Similarly, the vertical force saw substantial growth by 40.41% and 36.08% for every 5-centimeter increment. In contrast, the variation in draft force based on tillage depth was comparatively lower at 18.49% and 0.96%, indicating that the effect of tillage depth on draft force was less pronounced than its impact on shaft torque and vertical force. From a perspective of agricultural machinery research, this study provides valuable insights into the DEM soil modeling process, accounting for changes in soil properties with varying tillage depths. These findings are expected to be instrumental in future agricultural machinery design studies.