• Journal of Biosystems Engineering
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• v.33 no.2
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• pp.94-100
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• 2008

Present chemical application method using a power sprayer has been labor intensive, costly and ineffective. Therefore, a small agricultural unmanned helicopter was suggested to replace the conventional spray system. In this study, conceptual design for developing the helicopter and a consequential prototype were reported. The overall conceptual design was initiated by deciding the type of agricultural helicopter, as the single rotor helicopter with a tail system. As the first step of the designing, an air-cooled, 2-stroke engine was selected and a prototype transmission was designed by determining the rotating speed of main rotor shaft. A 'pusher' type tail rotor system was adapted to balance the reaction torque and reduce the power use. The tail boom length was designed to avoid the rotating trajectory of the main rotor. The RF console consisted of the engine control, attitude control, and emergency control modules. Assembling the prototype concluded the mechanical development of the agricultural helicopter.

• Journal of Biosystems Engineering
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• v.35 no.1
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• pp.31-36
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• 2010

A small unmanned helicopter was suggested to replace the conventional spray system. Aerial application using an agricultural helicopter helps precise and timely spraying, and reduces labor intensity and environmental pollution. In this research, a rotor system (SW05) was developed and its lift capability was evaluated. Lift force for the dead weight of the helicopter was obtained at the grip pitch angle of $12^{\circ}$. As the pitch angle increased to $14^{\circ}$ and $16^{\circ}$, the payload increased to 176 N and 216 N, respectively. Compared with SW04 airfoil performance in the total lift, the SW05 airfoil showed nearly the same capacity, but the payload of the SW05 was reduced because of the increased dead weight. A rated flight condition was defined as lifting mean payload of 294 N with the grip pitch angles of $16{\sim}17^{\circ}$ at the rotor rotating speed of 850~950 rpm for the adjusted engine power. The fuel consumption would be 4.8~6.0 L/hr, and the air temperature of cooling fan should be kept below $160^{\circ}C$.

• Proceedings of the Korean Geotechical Society Conference
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• 2008.03a
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• pp.511-520
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• 2008

The steel pipe strut for a means of the retaining structure has been used generally in North America, Europe and China so far. However, Korea and Japan, two countries are much familiar with H-shape steel strut having its anisotropic strength on two different axes(named as strong and weak axes), even though they recognize the steel pipe's excellence of structural function associated with its compressive ability. This trend is mainly due to a number of its field application, accumulated know-hows and workmanship etc. This paper introduces particular features of a high-strength steel pipe strut in comparison with the H-shape steel strut and its application for two excavation sites in Seoul. As a result of field verification, the high-strength pipe steel strut is more effective than the H-shape steel strut in terms of construction costs, schedules, constructibility and structural stability.

• Journal of the Ergonomics Society of Korea
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• v.31 no.6
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• pp.715-723
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• 2012

Objective: The aim of this study is to investigate haptic perception related researches into three perspectives: cutaneous & proprioceptive sensations, active & passive touch, and cognition & emotion, then to identify issues for implementing haptic interactions. Background: Although haptic technologies had improved and become practical, more research on the method of application is still needed to actualize the multimodal interaction technology. Systematical approached to explore haptic perception is required to understand emotional experience and social message, as well as tactile feedback. Method: Content analysis were conducted to analyze trend in haptic related research. Changes in issues and topics were investigated using sensational dimensions and the different contents delivered via tactile perception. Result: The found research opportunities were haptic perception in various body segments and emotion related proprioceptive sensation. Conclusion: Once the mechanism of how users perceives haptic stimuli would help to develop effective haptic interactrion and this study provide insights of what to focus for the future of haptic interaction. Application: This research is expected to provide presence, and emotional response applied by haptic perception to fields such as human-robot, human-device, and telecommunication interaction.

• Journal of Biosystems Engineering
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• v.31 no.3 s.116
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• pp.182-187
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• 2006

Aerial application using an unmanned agricultural helicopter can reduce labor and pollution. The development of an agricultural helicopter became urgent for both precise and timely spraying. In this study, a rotor system for unmanned helicopter capable of 20 $kg_f$ payload, was developed and lift capability was evaluated. A lift force over the dead weight of the helicopter was obtained at the pitch angle of $6^{\circ}$. As the pitch angle increased to $8^{\circ}\;and\;10^{\circ}$, the total lift increased to $74{\sim}81\;kg_f\;and\;86{\sim}93\;kg_f$, respectively. A range of engine speed at the rated flight condition, lifting mean payload of 23 $kg_f$ was determined. The data acquired from this study will be used for designing tail system and RF console in the next stage of the research. The rated lift capability was enough for loading 20 liters of spray material including spraying equipments.

• Journal of the Ergonomics Society of Korea
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• v.32 no.6
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• pp.557-563
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• 2013

Objective: This study introduces user experience measurement and its application for senior friendly products. Background: Measuring user experience for senior friendly product is very important for its design, but the measurement is not easy. Method: This study was focused on case studies for user experience measurement and its application for senior friendly product. Mobile patient lift and four wheeled walker that assist the old's mobility were studied. User experience was measured through interview and observation method. Result: From measuring the user experience, some usability issues were identified for the products. A method to apply QFD(quality function deployment) in design process was proposed. A design prototype was also developed considering user experience. Conclusion: User experience measurement for senior friendly products is key process for user centered design. Application: The method and result of this study can be applied to user experience measurement and design of senior friendly product.

• Journal of the Korean Ceramic Society
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• v.43 no.12 s.295
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• pp.839-845
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• 2006

Graphite has hexagonal closed packing structure with two bonding characteristics; (1) van der waals bonding between c axis, and (2) covalent bonding in the a and b axis. The weak van der waals bonds cause self-lubricant property, and the strong covalent bonds cause excellent electric and thermal conductivity. Furthermore, graphite is chemically very inert because of the material composed of only carbon elements. Thus, graphite is very useful for mechanical sealing materials. However, Graphite have porous microstructure because starting materials of graphite produce many volatile during the manufacturing processes. This causes low density of graphite, which is unsuitable for the mechanical sealing materials. Thus, further impregnation process is generally needed to enhance the graphite density. In this work, high density graphite is prepared with the principle of densification when coke and pitch binder, prepared from thermal treatment of coal tar pitch, become dehydrogenation during graphitization or carbonization.

• Journal of the Korean Society of Industry Convergence
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• v.26 no.3
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• pp.509-515
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• 2023

This study examind the product quality characteristics and industrial application of arrowroot powder added Yanggaeng before its industrial application. Several preliminary experiments were conducted by applying manufacturing conditions and varying the amount of arrowroot powder(1%, 2%, 3%, 4%) added to produce Yanggaeng recipes that can be sold commercially. The moisture content of the produce Yanggaeng was low due to the manufacturing standards, but it showed a significant increase with an increase in the ratio, which was similar to the results of other studies on Yanggaeng. The solubility, particale size distribution, and pH also showed a significant increasing trend. The hardness of arrowroot powder added Yanggaeng decreased with an increase in the amount of arrowroot powder, while springiness, gumminess, and chewiness increased with the addition of arrowroot powder. In terms of color, arrowroot powder showed a dark color, which was well suited to white bean paste and could also be used with black bean paste without any problem. These results were due to the manufacturing ratio being adjusted to meet commercial sales standards, resulting in a lower amount of water being used, and the characteristics of arrowroot powder being applied as they were.

• The Journal of Sustainable Design and Educational Environment Research
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• v.19 no.4
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• pp.78-87
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• 2020

This study proposed the basic data that contributes to inducing an effective construction plan through the application of the 4th industrial technology to construct a school building that can guarantee the five goals of construction management: cost, process, quality, safety, and environmental management. To this end, 3D printing, drones, robot automation, and augmented reality technologies that are highly usable in construction sites were identified for construction workers. As part of this, related literature and research data were investigated. The selected 4th industrial technology was investigated and analyzed on how it was used for cost, process, quality, safety, and environmental management in a detailed school construction process. As a result of the analysis, significant results were found for the application plan of the 4th industrial technology in school construction for cost, process, quality, safety, and environmental management.

• Journal of the Korean Society of Safety
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• v.38 no.1
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• pp.1-8
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• 2023

It is extremely important to design safety-guaranteed industrial processes because such process determine the ultimate outcomes of industrial activities, including worker safety. Application of artificial intelligence (AI) in industrial safety involves modeling industrial safety systems by using vast amounts of safety-related data, accident prediction, and accident prevention based on predictions. As a preliminary step toward realizing AI-based industrial safety in Korea, this study discusses neural network-based modeling of industrial safety systems. The input variables that are the most discriminatory relative to the output variables of industrial safety processes are selected using two information-theoretic measures, namely entropy and cross entropy. Normalized frequency and severity of industrial accidents are selected as the output variables. Our simulation results confirm the effectiveness of the proposed neural network model and, therefore, the feasibility of extending the model to include more input and output variables.