• The Korean Journal of Physiology and Pharmacology
• /
• v.17 no.3
• /
• pp.237-243
• /
• 2013

B13 is a ceramide analogue and apoptosis inducer with potent cytotoxic activity. A series of arylpropyl sulfonamide analogues of B13 were evaluated for their cytotoxicity using MTT assays in prostate cancer PC-3 and leukemia HL-60 cell lines. Some compounds (4, 9, 13, 14, 15, and 20) showed stronger activities than B13 in both tumor cell lines, and compound (15) gave the most potent activity with $IC_{50}$ values of 29.2 and 20.7 ${\mu}M$, for PC-3and HL-60 cells, respectively. Three-dimensional quantitative structure-activity relationship (3D-QSAR) analysis was performed to build highly reliable and predictive CoMSIA models with cross-validated $q^2$ values of 0.816 and 0.702, respectively. Our results suggest that long alkyl chains and a 1R, 2R configuration of the propyl group are important for the cytotoxic activities of arylpropyl sulfonamides. Moreover, the introduction of small hydrophobic groups in the phenyl ring and sulfonamide group could increase biological activity.

• International Journal of Contents
• /
• v.5 no.1
• /
• pp.51-55
• /
• 2009

In this paper, we present a structure of personalized e-Learning system to study for a test formalized by uniform multiple-choice using on/off line mixed estimations as is the case of Driver :s License Test in Korea. Using the system a candidate can study toward the license through the Internet (and/or mobile instruments) within the personalized concept based on IRT(item response theory). The system accurately estimates user's ability parameter and dynamically offers optimal evaluation problems and learning contents according to the estimated ability so that the user can take possession of the license in shorter time. In order to establish the personalized e-Learning concepts, we build up 3 databases and 2 agents in this system. Content DB maintains learning contents for studying toward the license as the shape of objects separated by concept-unit. Item-bank DB manages items with their parameters such as difficulties, discriminations, and guessing factors, which are firmly related to the learning contents in Content DB through the concept of object parameters. User profile DB maintains users' status information, item responses, and ability parameters. With these DB formations, Interface agent processes user ID, password, status information, and various queries generated by learners. In addition, it hooks up user's item response with Selection & Feedback agent. On the other hand, Selection & Feedback agent offers problems and content objects according to the corresponding user's ability parameter, and re-estimates the ability parameter to activate dynamic personalized learning situation and so forth.

• Journal of the Korean housing association
• /
• v.19 no.6
• /
• pp.85-93
• /
• 2008

This study analyzes areas, traffic lines and characteristics of block of traditional villages in order to suggest how to build urban village in the way that can solve problems occurring in residential areas these days. The study showed the following results: 1) Traditional villages have definite boundary and entrance, and the community area for the villages is close to the entrance to encourage community activities of villagers. 2) With an access in the form of a blind alley branched from the main road, traditional villages form a small-sized clustering and encourage community activities in a natural way. 3) Formed of block with a pattern of net, blind alley or standing in a line on both sides, traditional villages help residents to form close relations between. These findings suggest that for building desirable urban villages, 1) they should have definite boundary, 2) size and location of community area should be determined in the way to activate community activities of residents, 3) roads inside the village should have branched form rather than standardized check pattern so that small-sized clustering could be formed along the branched inner roads, and 4) clustering in villages should be arranged in a line on both sides or in the form of a blind alley giving consideration to the length and width of roads. The roads should be also of a closed type so that residents could create strong bonds with their neighbors.

• Journal of the Korean Institute of Rural Architecture
• /
• v.2 no.2
• /
• pp.115-126
• /
• 2000

Retaining walls are used to prevent excessive movement of retained soils. Typical retaining walls include gravity, reinforced concrete, reinforced earth and tie-back. However, from a practical viewpoint there are still drawbacks among these often constructed retaining walls. New types of retaining walls constructed with precast concrete blocks are proposed. This type of retaining wall is incorporates each blocks interconnected with adjacent block by connecting unit to build up a flexible retaining-wall system. This paper focus to behavior characteristics includes deformation and distribution of lateral earth pressure by loading tests and FEM analysis. For model tests, a 1/10 scale reduce models are manufactured include unevenness part, drainage hole and connecting unit and steel wire used to connect each blocks with adjacent block. To simulate the real retaining walls closely, uneven parts are interconnected each other and the construction type of blocks and wall front inclination are varied to investigate the relative displacement of individual block and the location of maximum deformation of wall as increasing surcharging. Additionally, PENTAGON3D, which solve the geotechnical and other problem, used for verifying and comparing with model tests.

• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2006.11a
• /
• pp.75-79
• /
• 2006

Recently, more highly effective construction materials are needed for the reasonable and economical structure system is required as the construction structures become more multi storied, large-sized and diversified. That is to say, the highly qualified concrete is positively promoted as a part of plan to establish the effective space according to the dead load of structures and diminish of segment profile and to build up the economic structures. However, the high strength concrete has the problems such high brittleness and low ductility. Specially, for the high strength concrete, it has different strength from normal concrete as the internal temperature goes up steadily due to high heat of hydration by the quantities of highly level of cement, so the concrete which is mixed with various miscible materials is used. As the development and study for high strength concrete (more than $100N/mm^2$) is under way actively and the strength of high strength concrete increases, the strength different from the existing high strength concrete of ten than $100N/mm^2$, but the study for this is not adequate and indefinite. In addition, the study and report to apply the strength expression and analysis results of internal structure. Therefore, this study is an experiment about using the miscible materials affects what happens to the longitudinal physical property.

• International Journal of Advanced Culture Technology
• /
• v.7 no.4
• /
• pp.40-48
• /
• 2019

Indoor gardens tailored to suit individual tastes offer a place to enjoy plants and to relax to city dwellers to relieve stress from city life. However, there are technical issues to build such indoor gardens. To offer solutions to technical issues, this study aims to analyze development phases of indoor garden-related technologies by studying available patents in detail. Also, the study aims to understand current status and future direction of technologies by examining technological trends for introduction of indoor gardens. Brainstorming method was used to understand technology trends and as a result, two groups were identified for technical features of indoor gardens: indoor greening technology and rest area for users. An analysis on selected patents showed that the number of patents increased until 2010 and declined gradually afterwards. Korea ranked the highest in the number of patents grant followed by USA, Japan and Europe. Similar order was observed with the number of patents granted by nationality of applicants. The number of patents granted by nationality was the highest for Korean nationals. For indoor greening technologies, patents related to structure from 2007 were mostly concentrated in the areas of irrigation control and environment control for plants and vegetation. For rest area related technologies, patent related to structure showed a repetitive pattern of increasing and decreasing, but overall, on downtrend. For further development and dissemination of indoor gardening technology, more R&D work is needed with focus on environmental control technology for designing suitable environment for both human and plant.

• International Journal of Naval Architecture and Ocean Engineering
• /
• v.6 no.3
• /
• pp.652-669
• /
• 2014

This paper concerns the kinematic characteristics of a coupling device in a deep-seabed mining system. This coupling device connects the buffer system and the flexible pipe. The motion of the buffer system, flexible pipe and mining robot are affected by the coupling device. So the coupling device should be considered as a major factor when this device is designed. Therefore, we find a stable kinematic device, and apply it to the design coupling device through this study. The kinematic characteristics of the coupling device are analyzed by multi-body dynamics simulation method, and finite element method. The dynamic analysis model was built in the commercial software DAFUL. The Fluid Structure Interaction (FSI) method is applied to build the deep-seabed environment. Hydrodynamic force and moment are applied in the dynamic model for the FSI method. The loads and deformation of flexible pipe are estimated for analysis results of the kinematic characteristics.

• Journal of Information Technology Services
• /
• v.15 no.4
• /
• pp.153-174
• /
• 2016

On account of multiple causes, including prolonged global economic crisis, addressing environmental pollution and the advent of hyper-connected society, a new paradigm called 'sharing economy' has rapidly emerged. Many startups have attempted to build promising business model based on the sharing economy concept. Nevertheless, successful cases are still very rare in the global level, except for Uber and Airbnb cases. Therefore, this study analyzes necessary causes and sufficient causes for successful settlements in the market through a comparative case analysis on digital matching firms in the sharing economy businesses. For the case study, we compare five successful cases (Uber, Airbnb, Kickstarter, TaskRabbit and DogVacay), three failure cases (Homejoy, Ridejoy and Tuterspree) and a platform cooperativism case (Juno) in accordance with six value attributes of business model including value proposition, market segment, value chain, cost structure and profit potential, value network and competitive strategy. We apply Boolean method to support controlled comparison and eliminate unnecessary attributes. The Boolean analysis result shows that value proposition, cost structure and profit potential, value network and competitive strategy are the essential attributes. Furthermore, the result indicates that each attribute is a necessary condition, where all four conditions should be met simultaneously in order to be successful. With this result, we discuss essential consideration for those who are planning startup based on the sharing economy business model.

• Korean System Dynamics Review
• /
• v.12 no.4
• /
• pp.35-62
• /
• 2011

PFI(Private Finance Initiative) for suppling SOC and public facilities instead of Government Infrastructure Project introduced from 1994. BTO(Build-Transfer-Operate) project had been major type of PFI system from 1994 to 2005. But after changed the Law of PFI on SOC, the BTL project newly introduced. In BTO system, the Government retrieves the investment through the operating income, but in BTL system, the government lease the facilities. As the BTO and BTL projects are widely adopted and implemented to ease the fiscal burden of government, but it has caused the tremendous fiscal burden each year over the period operation. Therefore this study attempted to analyze the question, that is, why government fiscal burden tipping? Hence, this paper, compares the difference of business structure between BTO and BTL project and explore the vicious and virtuous business structure, with the method of circular causal loop analysis. As a result, it has shown that there are some positive feedback and negative feedback loops cause the tipping and easing of government fiscal burden.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.23 no.7
• /
• pp.560-565
• /
• 2010

This paper presents the design factor of an overhead transmission tower structure in order to reduce the tower weight. The behaviour of transmission tower structures are affected by the horizontal angle of the tower structure, the equivalent wind pressure group, the slope of the main post of the tower, the separation of the internode and the use of high-strength materials in their construction. Tower weight can be reduced by approximately 30% reduce weight by means of optimal design based on a consideration of all the above factors. In addition, the design of the foundation of the tower with the shear key installation to increase horizontal support together with a modified angle of inclination to the ground can reduce by about 37% the amount of concrete used during construction. The area of ground disturbed by the construction of the tower foundation can thus be reduced by approximately 33%. Therefore it is possible to build an environmently-friendly T/L tower with the mechanical properties of existing towers.