• Journal of the Society of Naval Architects of Korea
• /
• v.41 no.4
• /
• pp.68-76
• /
• 2004

Inherent strain method for analyzing deformation of line-heating is substituting experiments of high cost, because of its high accuracy and quickness. Nowadays, the progressing forms of line-heating are not straight moving motions used to traditional studies, but weaving motions which can diversely input heat source. In shipyard, reasons of weaving motions are induction of a special characteristic by water cooling, maximum temperature limitation for keeping plates from melting, and rhythm for workman's maintaining velocity. On this study, a method which can obtain optimal weaving heating condition was presented, some examples were introduced, and the results corresponded to works of shipyard. Lastly, what the specifications of plates on efficiency are is presented, through the quality standard of shipyard and FEM heat transfer simulation. The ultimate purpose of line heating is the automation, so in case of plates which need weaving heating, the optimal heating condition suggested by this study can be used well in designing coil specifications of induction heaters which are heat input sources of new generation.

• Journal of the Ergonomics Society of Korea
• /
• v.17 no.2
• /
• pp.25-32
• /
• 1998

A combined PC and TV monitor has been developed in several companies. The characteristics of physical user interface in this monitor are likely to vary from existing monitors. Therefore, two experiments to investigate the physical interface characteristics of this monitor were conducted. The first experiment was to investigate the characteristics of color perception with monitor coating (coating vs. non-coating) and screen brightness (30fL vs. 35fL) in the PC mode. The second experiment was to investigate the characteristics of luminance contrast with monitor coating and image movement (static vs. dynamic) in the TV mode. Twenty-three subjects (male 12, female 11) were participated in this experiment. In the first experiment, average color temperatures were obtained in all experimental conditions. There was a significant difference between coating and non-coating screen at 0.1 level. In the second experiment, average luminance contrasts were obtained in all experimental conditions. There was a significant difference between coating and non-coating screen at 0.05 level. In addition, there was a significant difference between static picture and dynamic picture at 0.1 level.

• Journal of Institute of Control, Robotics and Systems
• /
• v.11 no.5
• /
• pp.445-450
• /
• 2005

In this paper, we suggest an integrated tactile display system that provides kinesthetic force, pressure distribution, vibration and slip/stretch. The system consists of two parts: a 2 DOF force feedback device for kinesthetic display and a tactile feedback device for displaying the normal stimulation to the skin and the skin slip/stretch. Psychophysical experiments measure the effects of fingerpad selection, the direction of finger movements and the texture width on tactile sensitivity. We also investigate the characteristics of lateral finger movement while subjects perceive different textures. From the experimental results, the principal parameters for designing a tactile display are suggested. A tactile display device, using eight piezoelectric bimorphs and a linear actuator, Is implemented and attached to a 2 DOF translational force feedback device to simultaneously simulate the texture and stiffness of the object. As a result, we find out that the capability of the suggested device is sufficient to display physical quantities to display the texture.

• Journal of Institute of Control, Robotics and Systems
• /
• v.12 no.5
• /
• pp.457-463
• /
• 2006

Recently proposed control scheme for a stable teleoperation, which was based on two-port time-domain passivity approach[21], has been successful for a contact with high stiffness environments. However, we found several conservatisms during the contact with deformable environments and unconstrained motion. The two-port time-domain passivity controller was excessively dissipating energy even though it was not necessary for some cases of an unconstrained motion and soft contact. The main reason of those conservatisms was on the fact that the two-port time-domain passivity controller was activated without considering the amount of energy dissipation at the master and slave manipulators. Especially, the exclusion of the slave manipulator from the two-port was the dominant reason of the conservatisms. In this paper, we consider the amount of energy dissipation at slave manipulator for designing the time-domain passivity observer and controller. The measured interaction force between slave manipulator and environment allow the time-domain passivity observer to include the amount of energy dissipation at the slave manipulator. Based on the modified passivity observer, reference energy following method[24] is applied to satisfy the passivity condition in real-time. The feasibility of the developed methods is proved with experiments. Improved performance is obtained for an interaction with deformable environments and an unconstrained motion.

• Journal of Power Electronics
• /
• v.14 no.5
• /
• pp.908-917
• /
• 2014

For the purpose of designing an intrinsic safety Flyback converter with minimal output voltage ripple based on a specified output current, this paper first classified the energy transmission modes of the system into three sorts, namely, the Complete Inductor Supply Mode-CCM (CISM-CCM), the Incomplete Inductor Supply Mode-CCM (IISM-CCM) and the Incomplete Inductor Supply Mode-DCM (IISM-DCM). Then, the critical secondary self-inductance assorting the three modes are deduced and expressions of the output voltage ripples (OVR) are presented. For a Flyback converter with constant loads and switching frequency, it is shown that the output voltage ripple in the CISM-CCM is the smallest and that it has no relationship with the secondary self-inductance. Otherwise, the OVR of the other two modes are bigger than the previously mentioned one. It is concluded that the critical inductance between the CISM-CCM and the IISM-CCM is the minimal secondary self-inductance to ensure the smallest output voltage ripple. At last, a design method to guarantee the minimum OVR within the scales of the input voltage and load are analyzed, and the minimum secondary self-inductance is proposed to minimize the OVR. Simulations and experiments are given to verify the results.

• Journal of the Ergonomics Society of Korea
• /
• v.31 no.4
• /
• pp.533-540
• /
• 2012

Objective: This paper targets a framework of a hand gesture based interface design. Background: While a modeling of contact-based interfaces has focused on users' ergonomic interface designs and real-time technologies, an implementation of a contactless interface needs error-free classifications as an essential prior condition. These trends made many research studies concentrate on the designs of feature vectors, learning models and their tests. Even though there have been remarkable advances in this field, the ignorance of ergonomics and users' cognitions result in several problems including a user's uneasy behaviors. Method: In order to incorporate compatibilities considering users' comfortable behaviors and device's classification abilities simultaneously, classification-oriented gestures are extracted using the suggested human-hand model and closed-loop classification procedures. Out of the extracted gestures, the compatibility-oriented gestures are acquired though human's ergonomic and cognitive experiments. Then, the obtained hand gestures are converted into a series of hand behaviors - Handycon - which is mapped into several functions in a mobile device. Results: This Handycon model guarantees users' easy behavior and helps fast understandings as well as the high classification rate. Conclusion and Application: The suggested framework contributes to develop a hand gesture-based contactless interface model considering compatibilities between human and device. The suggested procedures can be applied effectively into other contactless interface designs.

• Journal of the Korean Society of Manufacturing Process Engineers
• /
• v.16 no.5
• /
• pp.78-84
• /
• 2017

Compared to other types of power, hydraulic energy is the most commonly used for heavy vehicles and ships because it has fewer location and space constraints, and its controllability can be maintained even under adverse conditions. Operators have controlled a main control valve of ship winches by pushing or pulling the lever, which is directly connected to the spool. However, because of the spatial arrangement, the importance of remote control valves has emerged. In this paper, experiments of the hysteresis characteristics were performed by analyzing the remote-control valve using a valve tester and RA2300. The validity was verified by comparing with the analytical model using SimulationX as the hydraulic analysis program. This study examined the effects of the spool's notch (Non, End-mill, and Spherical) and the effects of stiffness and pre-load of the spool spring on Spool stroke, open area, and hysteresis characteristics. It is considered possible to reduce the cost and the, trial and error process in designing remote-control valves in the future.

• Bulletin of the Korean Chemical Society
• /
• v.31 no.12
• /
• pp.3521-3524
• /
• 2010

MTH1880 is a hypothetical protein derived from Methanobacterium thermoautotrophicum, thermophilic methanogen. The solution structure determined by NMR spectroscopy showed that it has a novel $\alpha+\beta$-fold with a highly acidic ligand binding pocket. Since MTH1880 maintains its ultra-stable structural characteristics at both high temperature and pressure, it has been considered as an excellent model for studying protein folding. To initiate the structural and folding study of MTH1880 in proving its unusual stability, we performed the site directed mutagenesis and biochemical analysis of MTH1880 mutants. Data from circular dichroism and NMR spectroscopy suggest that the point mutations perturbed the structural stability of protein even though the secondary structure is retained. This study will provide the useful information in understanding the role of participating residues during folding-unfolding process and our result will be used in designing further folding experiments for hyper-thermopile proteins like MTH1880.

• KIEAE Journal
• /
• v.9 no.1
• /
• pp.85-90
• /
• 2009

The indoor air quality is one of the most important issues of designing ventilation in high rise apartment buildings. This study suggested proper ventilation rate in the apartment bedroom where mechanical ventilation system has installed. Six university students(four male and two female) were participating in the experiment. Experiments were performed in environmental chamber. Experimental conditions were combinations from three ventilation rate 0, 0.4 and 0.7. Measurement items during 8 hours of experimental time were temperature, humidity, carbon dioxide concentrations and questionnaire surveyed aftrer sleeping. The concentration of Carbon Dioxide depending on ventilation rate in the chamber was analyzed for proper ventilation rate. The results of this paper can be summarized as follows. (1) When two persons experiment, 0.7 ventilation rate was in excess of 1000ppm. (2) When one person experiment, 0.7 and 0.4 ventilation rates were satisfied the criteria of IAQ. (3) It compared 0.4 with 0.7 in the ventilation rate, 0.4 ventilation rate could reduced about 80% of the power by fan similarity law.

• Smart Structures and Systems
• /
• v.20 no.6
• /
• pp.657-668
• /
• 2017

In this research, an active vibration suppression of a smart beam having piezoelectric sensor and actuators is investigated by designing separate controllers comprising a linear quadratic regulator and a neural network. Firstly, design of a smart beam which consists of a cantilever aluminum beam with surface bonded piezoelectric patches and a designed mechanism having a micro servomotor with a mass attached arm for obtaining variations in the frequency response function are presented. Secondly, the frequency response functions of the smart beam are investigated experimentally by using different piezoelectric patch combinations and the analytical models of the smart beam around its first resonance frequency region for various servomotor arm angle configurations are obtained. Then, a linear quadratic regulator controller is designed and used to simulate the suppression of free and forced vibrations which are performed both in time and frequency domain. In parallel to simulations, experiments are conducted to observe the closed loop behavior of the smart beam and the results are compared as well. Finally, active vibration suppression of the smart beam is investigated by using a linear controller with a neural network based adaptive element which is designed for the purpose of overcoming the undesired consequences due to variations in the real system.