• Smart Structures and Systems
• /
• v.9 no.5
• /
• pp.427-439
• /
• 2012

The present paper deals with the analytical solution of a functionally graded piezoelectric (FGP) cylinder in the magnetic field under mechanical, thermal and electrical loads. All mechanical, thermal and electrical properties except Poisson ratio can be varied continuously and gradually along the thickness direction of the cylinder based on a power function. The cylinder is assumed to be axisymmetric. Steady state heat transfer equation is solved by considering the appropriate boundary conditions. Using Maxwell electro dynamic equation and assumed magnetic field along the axis of the cylinder, Lorentz's force due to magnetic field is evaluated for non homogenous state. This force can be employed as a body force in the equilibrium equation. Equilibrium and Maxwell equations are two fundamental equations for analysis of the problem. Comprehensive solution of Maxwell equation is considered in the present paper for general states of non homogeneity. Solution of governing equations may be obtained using solution of the characteristic equation of the system. Achieved results indicate that with increasing the non homogenous index, different mechanical and electrical components present different behaviors along the thickness direction. FGP can control the distribution of the mechanical and electrical components in various structures with good precision. For intelligent properties of functionally graded piezoelectric materials, these materials can be used as an actuator, sensor or a component of piezo motor in electromechanical systems.

• Journal of Korean Clinical Health Science
• /
• v.7 no.2
• /
• pp.1289-1297
• /
• 2019

Purpose: The purpose of this study was to investigate occupational therapy at M college in Changwon and the impact of smart phone use on the school life of college students and to help them find ways to further develop in the future. Methods; Data collection was conducted using questionnaires, and the questionnaires consisted of 152 total questions with 15 interpersonal questions, 23 problem solving skills, 43 self-efficacy, 16 class participation scale, and 55 self-directed learning scale. It was conducted to first and second graders of M college and conducted a survey through the corresponding academic year from March 26, 2019 to March 29, 2019 to retrieve 120 questionnaires and use them for analysis. The collected data were analyzed using SPSS. Statistic 20.0. Results: Studies show that "school life satisfaction" is usually the highest at 53 percent. The "smartphone user motivation" was the highest with 50.8 percent, while the "most frequently used feature on smartphones" was the highest with 57.5 percent on SNS. Satisfaction after using a smartphone was the highest with 49.2 percent, while 41.7 percent said it would be easier to acquire and utilize information in the areas of satisfaction. Conclusion: Smartphone addiction, interpersonal relationships, problem-solving skills, self-efficacy, participation in classes, and self-control learning items are not only affected by one part, but also by the other.

• The Journal of Information Systems
• /
• v.29 no.2
• /
• pp.197-220
• /
• 2020

Purpose Cloud computing that provides a new paradigm for a firm's use of information technology is getting a lot of attentions by practitioners. However, the empirical investigation on members of organizations using cloud computing are insufficient. Therefore, this study aims to examine the capabilities and perceptions of organizational members that should be considered important for successful cloud computing implementation. Design/methodology/approach This study proposed factors related to the capabilities and perceptions of members of the organization, and examined the relationship between these factors and successful cloud computing implementation and performance. In addition, this study tested the moderating effect of leadership and continuous supports through empirical analysis. The proposed hypotheses were verified through structural equation modeling using SmartPLS3.0 with the collected data. Findings The results showed that four factors except 'member behavior control' had a positive effect on successful cloud computing implementation, which had a positive effect on performance. In addition, leadership and organizational continuous support have been shown to strengthen the relationship among factors.

• Journal of the Korean Society of Industry Convergence
• /
• v.22 no.3
• /
• pp.373-379
• /
• 2019

Nowadays, the IoT portable electronic devices have become more useful and diverse, so they require various supply voltage levels to operate. This paper presents a DC-DC buck converter with pulse width modulation (PWM) for portable electronic devices. The proposed step-down DC-DC converter consists of passive elements such as capacitors, inductors, and resistors and an integrated chip (IC) for signal control to reduce power consumption and improves ripple voltage with the resolution. The proposed DC-DC converter is simulated and analyzed in PSPICE circuit design platform, and implemented on the prototype PCB board with a Texas Instruments LM5165 IC. The proposed buck converter is showed 92.6% of peak efficiency including a load current range of 4-10 mA, 3.29 mV of the voltage ripple at 5 V output voltage for the supply voltage 12 V. Measured and Simulated power efficiency are made good agreement with each other.

• International journal of advanced smart convergence
• /
• v.10 no.3
• /
• pp.187-197
• /
• 2021

We present following research summary and implications through the analysis of the research. First, the before the opening of public cremation facilities compared to new opening of those, the number of the corpse cremation increases to annual average of 5.5% of the rate, and it has a positive effect on increasing rate of the cremation. Therefore, a policy of expanding the supply of public cremation facilities should be pursued to improve cremation rate in the area of uninstalled public cremation facilities. Second, the before the opening of public cremation facilities compared to new opening of those, the number of the corpse cremation has increased to the annual average 3,623 people(56.9%) at jurisdiction area, while it has decreased to 949 people (28.3%) at the out of the jurisdiction area. The active efforts and building the funding expansion should be made to establish public cremation facilities of the central and local governments to improve convenience of the use of public cremation facilities. Third, since the before and after opening of public cremation facilities at Jeongeup City lead to great effect on demand of jurisdiction area and out of the jurisdiction area, the cremation demand should be reduced through the supply expansion of public cremation facilities and differentiation strategy to control cremation demand at the out of the jurisdiction area, focusing on metropolitan areas with high cremation demand, such as metropolitan areas or metropolitan cities.

• IEIE Transactions on Smart Processing and Computing
• /
• v.6 no.4
• /
• pp.299-304
• /
• 2017

A wireless passive sensor network is a network consisting of sink nodes, sensor nodes, and radio frequency (RF) sources, where an RF source transfers energy to sensor nodes by radiating RF waves, and a sensor node transmits data by consuming the received energy. Against theoretical expectations, a wireless passive sensor network suffers from many practical difficulties: scarcity of energy, non-simultaneity of energy reception and data transmission, and inefficiency in allocating time resources. Perceiving such difficulties, we propose a simple contending-type medium access control (MAC) scheme for many sensor nodes to deliver packets to a sink node. Then, we derive an approximate expression for the network-wide throughput attained by the proposed MAC scheme. Also, we present an approximate expression for the optimal partition, which maximizes the saturated network-wide throughput. Numerical examples confirm that each of the approximate expressions yields a highly precise value for network-wide throughput and finds an exactly optimal partition.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.10 no.12
• /
• pp.5286-5306
• /
• 2016

Emerging applications in automation, medical imaging, traffic monitoring and surveillance need real-time data transmission over Wireless Sensor Networks (WSNs). Guaranteeing Quality of Service (QoS) for real-time traffic over WSNs creates new challenges. Rapid penetration of smart devices, standardization of Machine Type Communications (MTC) in next generation 5G wireless networks have added new dimensions in these challenges. In order to satisfy such precise QoS constraints, in this paper, we propose a new cross-layer QoS-provisioning strategy in Wireless Multimedia Sensor Networks (WMSNs). The network layer performs statistical estimation of sensory QoS parameters. Identifying QoS-routing problem with multiple objectives as NP-complete, it discovers near-optimal QoS-routes by using evolutionary genetic algorithms. Subsequently, the Medium Access Control (MAC) layer classifies the packets, automatically adapts the contention window, based on QoS requirements and transmits the data by using routing information obtained by the network layer. Performance analysis is carried out to get an estimate of the overall system. Through the simulation results, it is manifested that the proposed strategy is able to achieve better throughput and significant lower delay, at the expense of negligible energy consumption, in comparison to existing WMSN QoS protocols.

• Journal of the Korean Society of Industry Convergence
• /
• v.25 no.2_2
• /
• pp.299-307
• /
• 2022

Wireless earphones, along with smart devices, are the most sought-after products by consumers. Compared to general earphones, wireless earphones do not have twisted wires and are easy to use, so various types of products are currently on the market. However, information on quality is somewhat lacking, so consumers tend to purchase products according to brand awareness, and manufacturers are delivering information to consumers using different standards for each product because there is no standard for quality control. In particular, the playback time of wireless earphones is a factor that directly affects consumers' purchases, so a standard measurement method is needed to properly measure it. In this paper, we present a method for measuring the audio playback time of wireless earphones derived from domestic wireless earphone status survey, commercial product measurement test, and research analysis, and a developed standard measurement method. In addition, this paper proposes a measurement result reporting format to provide accurate information to consumers and induce a fair competitive environment for each product to manufacturers.

• Journal of Bio-Environment Control
• /
• v.32 no.3
• /
• pp.197-204
• /
• 2023

Heat stress causes a decrease in immunity and disease occurrence in livestock, increasing mortality and impairing productivity. In particular, chickens are very vulnerable to high temperatures compared to other livestock species because their entire body is covered with feathers and sweat glands are not developed. Currently, air conditioning systems are essential in broiler houses to prevent high-air temperature damage to broilers, but conventional cooling facilities are greatly affected by the external environment, so there are limits to their use. In this study, to propose a cooling method, thermal insulation paint and a heat pump were apply in the broiler houses to evaluate the temperature reduction effect. The heat pump experiment was to analyze the cooling effect according to the change in ventilation rate and propose an appropriate. As a result of the experiment, the heat-insulating paint reduced the temperature of the broiler houses by maximum 1-2℃, and in the broiler houses where the heat pump was operated, the temperature decrease was the largest when the ventilation rate was the lowest. When the air temperature in the house is similar to or lower than the outside air temperature, it is considered to be most effective to use a heat pump while maintaining only the minimum ventilation rate.

• Journal of the Korean Solar Energy Society
• /
• v.31 no.6
• /
• pp.72-77
• /
• 2011

The purpose for installation of offshore weather station is a measurement of wind resources and so on. If weather station is operated, it will be possible to analysis for wind resource and arrangement of wind farm by using measured data. In this paper, we carried out the development of offshore wind resource measurement system for measuring offshore wind resource. Also, In order to monitor for real-time wind data with 1 Hz, we installed the wireless transmission system. All wind characteristic data are sent to the server PC through the this system is connected outport of DataLogger. Transmitted wind data were used in order to look at in the Web-page and tablet PC on a real time basis in a graph. In this paper, we will introduce about the wind resource measurement and remote monitoring system that is the result of study.