• Journal of Ocean Engineering and Technology
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• v.23 no.6
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• pp.32-38
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• 2009

An FMEA for the waterjet-lifter of a DSNM is performed to prevent the occurrence of device failure. A waterjet-lifter raises and transports manganese nodules from the deep-sea floor up to a somewhat elevated place, from which a pin-scraper transports the lifted nodules to the inner space of the DSNM. A concept design for a device using the axiomatic design methodology is shown as the mapping between the functional domain and physical domain. The FMEA for a DSNM is introduced briefly and the rating criteria of severity, occurrence, and detection for the DSNM are defined. The FMEA of the functional requirements of a DSNM device is accomplished. Three kinds of failure modes, as well as their effects and causes, are predicted. Current design control methods for detecting potential failures, such as physical or computational experiments, design confirmation, and mathematical calculation, are described and the recommended actions for several significant causes are suggested.

• Journal of the Ergonomics Society of Korea
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• v.17 no.2
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• pp.25-32
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• 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 the Korea Concrete Institute
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• v.17 no.6 s.90
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• pp.1053-1064
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• 2005

The mechanical damage of concrete is normally attributed to the formation of microcracks and their propagation and coalescence into macroscopic cracks. This physical degradation is caused from progressive and hierarchical damage of the microstructure due to debonding and slip along bimaterial interfaces at the mesoscale. Their growth and coalescence leads to initiation of hairline discrete cracks at the mesoscale. Eventually, single or multiple major discrete cracks develop at the macroscale. In this paper, from this conceptual model of mechanical damage in concrete, the computational efforts were made in order to characterize physical cracks and how to quantify the damage of concrete materials within the laws of thermodynamics with the aid of interface element in traditional finite element methodology. One dimensional effective traction/jump constitutive interface law is introduced in order to accommodate the normal opening and tangential slips on the interfaces between different materials(adhesion) or similar materials(cohesion) in two and three dimensional problems. Mode I failure and mixed mode failure of various geometries and boundary conditions are discussed in the sense of crack propagation and their spent of fracture energy under monotonic displacement control.

• ETRI Journal
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• v.34 no.3
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• pp.352-360
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• 2012

This paper proposes a low-cost, low-power, and high-capacity optical-electrical-optical-type reach extender that can provide 3R frame regeneration and remote management to increase the reach and split ratio with no change to a legacy time division multiple access passive optical network. To provide remote management, the extender gathers information regarding optical transceivers and link status per port and then transmits to a service provider using a simple network management protocol agent. The extender can also apply to an Ethernet passive optical network (E-PON) or a gigabit-capable PON (G-PON) by remote control. In a G-PON, in particular, it can provide burst mode signal retiming and burst-to-continuous mode conversion at the upstream path through a G-PON transmission convergence frame adaptor. Our proposed reach extender is based on the quad-port architecture for cost-effective design and can accommodate both the physical reach of 60 km and the 512 split ratios in a G-PON and the physical reach of 80 km and the 256 split ratios in an E-PON.

• Nuclear Engineering and Technology
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• v.49 no.3
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• pp.484-494
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• 2017

In industrial plants such as nuclear power plants, system operations are performed by embedded controllers orchestrated by Supervisory Control and Data Acquisition (SCADA) software. A targeted attack (also termed a control aware attack) on the controller/SCADA software can lead a control system to operate in an unsafe mode or sometimes to complete shutdown of the plant. Such malware attacks can result in tremendous cost to the organization for recovery, cleanup, and maintenance activity. SCADA systems in operational mode generate huge log files. These files are useful in analysis of the plant behavior and diagnostics during an ongoing attack. However, they are bulky and difficult for manual inspection. Data mining techniques such as least squares approximation and computational methods can be used in the analysis of logs and to take proactive actions when required. This paper explores methodologies and algorithms so as to develop an effective monitoring scheme against control aware cyber attacks. It also explains soft computation techniques such as the computational geometric method and least squares approximation that can be effective in monitor design. This paper provides insights into diagnostic monitoring of its effectiveness by attack simulations on a four-tank model and using computation techniques to diagnose it. Cyber security of instrumentation and control systems used in nuclear power plants is of paramount importance and hence could be a possible target of such applications.

• Journal of Korea Multimedia Society
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• v.21 no.11
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• pp.1342-1352
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• 2018

Voice Command systems are important means of ensuring accessibility to digital devices for use in situations where both hands are not free or for people with disabilities. Interests in services using speech recognition technology have been increasing. In this study, we developed a mobile writing application using voice recognition and voice command technology which helps people create and edit documents easily. This application is characterized by the minimization of the touch on the screen and the writing of memo by voice. We have systematically designed a mode to distinguish voice writing and voice command so that the writing and execution system can be used simultaneously in one voice interface. It provides a shortcut function that can control the cursor by voice, which makes document editing as convenient as possible. This allows people to conveniently access writing applications by voice under both physical and environmental constraints.

• Smart Structures and Systems
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• v.30 no.1
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• pp.107-119
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• 2022

Modal parameters are widely used in bridge damage detection, finite element model (FEM) updating and design optimization. However, the conventional modal identification approaches require large number of sensors, enormous data processing workload, but normally result in mode shapes with low accuracy. This paper proposes a modal identification method of time-varying vehicle-bridge system using a single sensor. Firstly, the essential physical relationship between the instantaneous frequency of the vehicle-bridge system and the bridge mode shapes are derived. Subsequently, based on the synchroextracting transform, the instantaneous frequency of the system is tracked through the dynamic response collected by a single sensor, and further the modal parameters are estimated by using the derived physical relationship. Then numerical and experimental examples are conducted to examine the feasibility and effectiveness of the proposed method. Finally, the modal parameters identified by the proposed method are applied in bridge FEM updating. The results manifest that the proposed method identifies the modal parameters with high accuracy via a single sensor, and can provide reliable data for the FEM updating.

• Journal of Korean Academy of Fundamentals of Nursing
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• v.3 no.2
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• pp.213-233
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• 1996

This study was made on 274 apoplectics patients who received the rehabilitation therapy and tests on physical, psychological and social adaptations as outpatients in 23 general hospitals in the Seoul and Kyungi area. The basic data on degree of improvement of apoplectic patients studied from rehabilitation therapy. Data was collected over a period of 63 days, from February 21st till April, 23, 1996. The assigned physical therapist conducted direct interviews with patients after he answered the distributed questionnaires for each individual patient. The colleted data was processed by the $SPCC/C^+$ method. The results of the tests conducted to meascne the the degree of ADL dependency, depression and social activity corresponding to the physical, psychological, and social adaptation. The details are ; 1) The test to meascne the degree of ADL dependency, corresponding to the study of physical adaptation of CVA patients, indicated a mean score of 2.57(ideal score is 1.0) with a standard deviation of ${\pm}0.75$. The worst score was 3.95 while the best score was a perfect 1.0, representing a severe range of dependency. The distribution was centered with a median of 2.65 and a mode of 2.68. 2) The test to meascne the degree of depression which corresponds to the level of psychological adaptation yielded a mean of 2.99 which is higher than the normal limit of 2.45. The standard deviation was ${\pm}0.52$ and the worst score and the best score were 4.35 and Respectirdy. The distribution was centered with a median of 3.00 and a mode of 3.00. 3) The test to meascne the degree of social activities for the level of social adaptation indicated a very low mean score of 26.52 (perfect score is 144), with the standard deviation of ${\pm}16.23$. Some patients scored as high as 100, but others scored as low as 3. The distribution of social activities at a very low level was shifted to the left with a median of 24.00 and a mode of 20.00. 4) Factors influencing the level of physical, psychological and social adaptation are as follows : Factors significantly influencing the level of physical adaptation measured by ADL dependency are age, personal guardian, payer of medical expenses, and paralysis of the right arm, right leg and facial paralysis. Factors significantly influencing the level of psychological adaptation measured by the degree of depression, are age, marital status, education, medical history of individual and family, speech impediment, and facial paralysis. Factors significantly influencing the level of social adaptation measured by the degree of social activity are age, marital status, education, employment status, and the burden of medical expense. 5) The Corelationship is significant(9.00), between ADL dependeing as degree of physical adaptation and depreseion as degree of psychologial adaptation. ADL dependency is proportional to depression. But social activity is inversely protional to ADL dependeny and depression. In conclusion, the increased care for physical function of the patients is not the only necessary means to better facilitate the appropriate adaptation of CVA patients. The introduction of a solid rehabilitation program for psychological and social adaptation will also play the integral part of the treatment of CVA patients.

• Geophysics and Geophysical Exploration
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• v.10 no.1
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• pp.1-18
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• 2007

Non-linear elastic wavefield inversion is a powerful method for estimating elastic parameters for physical constraints that determine subsurface rock and properties. Here, I introduce six elastic-wave velocity models by reconstructing elastic-wave velocity variations from real data and a 2D elastic-wave velocity model. Reflection seismic data information is often decoupled into short and long wavelength components. The local search method has difficulty in estimating the longer wavelength velocity if the starting model is far from the true model, and source frequencies are then changed from lower to higher bands (as in the 'frequency-cascade scheme') to estimate model elastic parameters. Elastic parameters are inverted at each inversion step ('simultaneous mode') with a starting model of linear P- and S-wave velocity trends with depth. Elastic parameters are also derived by inversion in three other modes - using a P- and S-wave velocity basis $('V_P\;V_S\;mode')$; P-impedance and Poisson's ratio basis $('I_P\;Poisson\;mode')$; and P- and S-impedance $('I_P\;I_S\;mode')$. Density values are updated at each elastic inversion step under three assumptions in each mode. By evaluating the accuracy of the inversion for each parameter set for elastic models, it can be concluded that there is no specific difference between the inversion results for the $V_P\;V_S$ mode and the $I_P$ Poisson mode. The same conclusion is expected for the $I_P\;I_S$ mode, too. This gives us a sound basis for full wavelength elastic wavefield inversion.

• The Journal of Korean Physical Therapy
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• v.19 no.2
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• pp.11-19
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• 2007

Purpose: The purpose of this study were to analyze ultrasonography on both sides of gastrocnemius medialis of stroke patient. Methods: In fourteen subjects with stroke, the gastrocnemius medialis(GM) muscle were scanned with ultrasonography at the muscle belly at rest at ankle angles of 0 degree (neutral position) and it were measured with ultrasonography on both sides of the leg. Muscle architecture (thickness, pennation angle, fascicle length, density, white area index) was examined using real-time B-mode ultrasonography with 7.5MHz linear-array prob. Results: Thickness of non-paratic side was significantly thicker than paratic side. Pennation angle of non-paratic side was significantly larger than paratic side. Fascicle length of non-para tic side was significantly smaller than paratic side. Density of non-paratic side was significantly smaller than paratic side. White area index of non-paranc side was significantly smaller than paratic side. Conclusion: This study showed that stroke have influenced on mechanical properties and quality properties of skeletal muscle architecture.