• Journal of the Korean Geotechnical Society
• /
• v.28 no.11
• /
• pp.33-40
• /
• 2012

The design of Piled Raft foundations considering the load sharing between raft and piles provides a more economical solution than the conventional design approach based on bearing capacity of piles only. Generally, numerical methods are used to analyze the behavior of Piled Rafts due to its complexity and load sharing ratio is also estimated by numerical methods about some limited cases under specific load level and soil conditions. In this study, a method to estimate the load sharing between the raft and piles was developed which is based on load-settlement characteristics of foundation elements. Normalized load-settlement curves of the raft and pile groups were derived individually, and the relationship between load sharing ratio and foundation settlement was proposed by using these curves. For each load-settlement curves, hyperbolic type was adopted in order to describe the non-linear behavior of foundations. Centrifuge test results were compared with the results from proposed method, and the trends of variation of load sharing ratio with settlement presented from both were similar.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.38 no.12
• /
• pp.1057-1064
• /
• 2014

Recently, there has been a growing interest in sustainable energy. One method that has been used is an organic Rankine cycle using conventional turbine technology with a low-temperature waste heat source. A 200-kW organic Rankine cycle (ORC) system was designed for a waste heat recovery application using R245fa as the working fluid. A radial turbine running at 15,000 rpm was employed to generate more than 200 kW with an expansion ratio of nine. Because an ORC turbine uses a refrigerant as the working fluid, the ideal gas law was not employed to design the turbine. In addition, the complexity of the molecular structure of R245fa made it difficult to design the turbine. Because R245fa has an Ma value of one at a low velocity for the working fluid (about 1/3 of the speed of sound in air) at about $100^{\circ}C$, it easily reaches a supersonic flow condition with a small pressure expansion. To increase the efficiency of the turbine, a dual stage radial-type turbine with a subsonic speed was suggested. This paper will describe the design procedure and performance evaluation of the ORC turbine using R245fa.

• Journal of Korea Water Resources Association
• /
• v.52 no.8
• /
• pp.545-554
• /
• 2019

The most drought assessments are based on a drought index, which depends on univariate variables such as precipitation and soil moisture. However, there is a limitation in representing the drought conditions with single variables due to their complexity. It has been acknowledged that a multivariate drought index can more effectively describe the complex drought state. In this context, this study propose a Copula-based drought index that can jointly consider precipitation and soil moisture. Unlike precipitation data, long-term soil moisture data is not readily available so that this study utilized a Gaussian Mixture Non-Homogeneous Hidden Markov chain Model (GM-NHMM) model to simulate the soil moisture using the observed precipitation and temperature ranging from 1973 to 2014. The GM-NHMM model showed a better performance in terms of reproducing key statistics of soil moisture, compared to a multiple regression model. Finally, a bivariate frequency analysis was performed for the drought duration and severity, and it was confirmed that the recent droughts over Jeollabuk-do in 2015 have a 20-year return period.

• KIPS Transactions on Computer and Communication Systems
• /
• v.11 no.10
• /
• pp.323-332
• /
• 2022

As various services using AI technology are being developed, much attention is being paid to AI service production. Recently, AI technology is acknowledged as one of ICT services, a lot of research is being conducted for general-purpose AI service production. In this paper, I describe the research results in terms of systems for AI service production, focusing on the distribution and production of machine learning models, which are the final steps of general machine learning development procedures. Three different Ubuntu systems were built, and experiments were conducted on the system, using data from 2017 validation COCO dataset in combination of different AI models (RFCN, SSD-Mobilenet) and different communication methods (gRPC, REST) to request and perform AI services through Tensorflow serving. Through various experiments, it was found that the type of AI model has a greater influence on AI service inference time than AI machine communication method, and in the case of object detection AI service, the number and complexity of objects in the image are more affected than the file size of the image to be detected. In addition, it was confirmed that if the AI service is performed remotely rather than locally, even if it is a machine with good performance, it takes more time to infer the AI service than if it is performed locally. Through the results of this study, it is expected that system design suitable for service goals, AI model development, and efficient AI service production will be possible.

• Journal of Broadcast Engineering
• /
• v.18 no.2
• /
• pp.237-248
• /
• 2013

Hybrid broadcasting environment is convergence of broadcasting and communication environment. In hybrid broadcasting environment, a number of media can be delivered using both broadcasting channel and other network unlike traditional broadcast environment that is able to deliver a couple of media by the limited bandwidth. Now, starting with smart TV, hybrid broadcasting environment combining broadcasting channel and IP network is established, and a variety of services are appearing. Moreover, the services using hybrid broadcasting environment are expected to appear soon for the other smart terminals such as smart phone and tablet PC. Scene composition is one of the methods that can consume effectively a number of media delivered from hybrid broadcasting environment. Using scene composition, multiple media can be consumed through the specified presentation time and space. Therefore, in this paper, it proposes the scene composition technology that is suitable for hybrid broadcasting environment and smart terminals. However, the spatial composition and temporal composition of media using script language and style language of HTML5 might increase the complexity of processing, and cause limitation of avaliable terminals. Also, a document of HTML5 can describe only one scene. By these reason, the proposed scene composition technology extends HTML5 in order to provide the spatial and temporal composition of media and description of multiple scene through markup language. In addition, it includes the extension of HTML5 in terms of utilization in hybrid broadcasting environment. For this proposal, this paper describes the technology of HTML5 and proposed scene composition. Also, it verifies the scene composition with both implementations and experiments.

• Korean journal of applied entomology
• /
• v.61 no.1
• /
• pp.129-142
• /
• 2022

Nutrition dictates nearly all biological processes and determines Darwinian fitness in all living organisms, including insects. Research on insect nutrition has a long history in the field of insect physiology and the importance of understanding insect nutrition has become increasingly apparent with the growing need for producing insects as food and feed. Nevertheless, it is only in recent years that we have witnessed a major breakthrough in our knowledge of insect nutrition. The multivariate, interactive, and dynamic nature of nutrition has long hampered our complete understanding of insect nutrition. However, the challenge posed by such nutritional complexity has been overcome with the advent of the Nutritional Geometry, which is an integrative and multidimensional framework that enabled us to model complex interactions between multiple nutrients. In this review, we introduce the basic concepts and principles of the Nutritional Geometry and describe how this innovative framework has revolutionized the field of insect nutrition and has placed nutrition in the centre of the interface between physiology, ecology, and evolution. We close this review by discussing potentially fertile research areas that can benefit tremendously from the application of this powerful nutritional paradigm in the future.

• Information Systems Review
• /
• v.14 no.1
• /
• pp.85-103
• /
• 2012

ISMP is a method of writing clearly the user requirements in the RFP(Request for Proposal) of the IS development projects. Unlike the conventional methods of RFP preparation that describe the user requirements of target systems in a rather superficial manner, ISMP systematically identifies the businesses needs and the status of information technology, analyzes in detail the user requirements, and defines in detail the specific functions of the target systems. By increasing the clarity of RFP, the scale and complexity of related businesses can be calculated accurately, many responding companies can prepare proposals clearly, and the level of fairness during the evaluation of many proposals can be improved, as well. Above all though, the problems that are posed as chronic challenges in this field, i.e., the misunderstanding and conflicts between the users and developers, excessive burden on developers, etc. can be resolved. This study is a case study that analyzes the execution process, execution accomplishment, problems, and the success factors of two pilot projects that introduced ISMP for the first time. ISMP performance procedures of actual site were verified, and how the user needs in the request for quote are described was examined. The satisfaction levels of ISMP RFP for quote were found to be high as compared to the conventional RFP. Although occurred were some problems such as RFP preparation difficulties, increased workload, etc. due to the lack of understanding and execution experience of ISMP, in overall, also occurred were some positive effects such as the establishment of the scope of target systems, improved information sharing and cooperation between the users and the developers, seamless communication between issuing customer corporations and IT service companies, reduction of changes in user requirements, etc. As a result of conducting action research type in-depth interviews on the persons in charge of actual work, factors were derived as ISMP success factors: prior consensus on the need for ISMP, the acquisition of execution resources resulting from the support of CEO and CIO, and the selection of specification level of the user requirements. The results of this study will provide useful site information to the corporations that are considering adopting ISMP and IT service firms, and present meaningful suggestions on the future study directions to researchers in the field of IT service competitive advantages.