• JSTS:Journal of Semiconductor Technology and Science
• /
• v.8 no.3
• /
• pp.221-226
• /
• 2008

A new two dimensional (2-D) analytical model for the Threshold Voltage on dual material surrounding gate (DMSG) MOSFETs is presented in this paper. The parabolic approximation technique is used to solve the 2-D Poisson equation with suitable boundary conditions. The simple and accurate analytical expression for the threshold voltage and sub-threshold swing is derived. It is seen that short channel effects (SCEs) in this structure is suppressed because of the perceivable step in the surface potential which screens the drain potential. We demonstrate that the proposed model exhibits significantly reduced SCEs, thus make it a more reliable device configuration for high speed wireless communication than the conventional single material surrounding gate (SMSG) MOSFETs.

• Smart Structures and Systems
• /
• v.17 no.4
• /
• pp.631-646
• /
• 2016

Although the deployment of wireless sensors for structural sensing and monitoring is becoming popular, supplying power to these sensors remains as a daunting task. To address this issue, there have been large volume of ongoing energy harvesting studies that aimed to find a way to scavenge energy from surrounding ambient energy sources such as vibration, light and heat. In this study, a magnetic resonance based wireless power transfer (MR-WPT) system is proposed so that sensors inside a concrete structure can be wirelessly powered by an external power source. MR-WPT system offers need-based active power transfer using an external power source, and allows wireless power transfer through 300-mm thick reinforced concrete with 21.34% and 17.29% transfer efficiency at distances of 450 mm and 500 mm, respectively. Because enough power to operate a typical wireless sensor can be instantaneously transferred using the proposed MR-WPT system, no additional energy storage devices such as rechargeable batteries or supercapacitors are required inside the wireless sensor, extending the expected life-span of the sensor.

• IEMEK Journal of Embedded Systems and Applications
• /
• v.1 no.2
• /
• pp.82-89
• /
• 2006

It appears that it is possible for us to make a wireless communication of even home-network system within car by integrating with the Ubiquitous such as mobile phone, wireless Internet, GPS and DMB in the future. If the present wireless surroundings within the car are connected with very high-speed wireless network as measurement system for wireless communication surroundings within this car in the future, it will develop the complicated communication conditions such as safe checkup, communication between systems within car, and wireless communication for user entertainment unlike universal communication conditions. Accordingly, there is the necessity of the device that can measure the interference of electric wave, communication speed and communication quality by a kind of each car. This paper aims at making the real measurement device to raise the reliability of each Application for inquiring into the interference about each other in the frequency band used under Telematics surroundings.

• IEIE Transactions on Smart Processing and Computing
• /
• v.4 no.3
• /
• pp.133-140
• /
• 2015

Neural stimulating implantable medical devices (IMDs) have been widely used to treat neurological diseases or interface with sensory feedback for amputees or patients suffering from severe paralysis. More recent IMDs, such as retinal implants or brain-computer interfaces, demand higher performance to enable sophisticated therapies, while consuming power at higher orders of magnitude to handle more functions on a larger scale at higher rates, which limits the ability to supply the IMDs with primary batteries. Inductive power transmission across the skin is a viable solution to power up an IMD, while it demands high power efficiencies at every power delivery stage for safe and effective stimulation without increasing the surrounding tissue's temperature. This paper reviews various wireless neural stimulating systems and their power management techniques to maximize IMD power efficiency. We also explore both wireless electrical and optical stimulation mechanisms and their power requirements in implantable neural interface applications.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.7 no.5
• /
• pp.1077-1093
• /
• 2013

This paper proposes a new network coordinator node design to select the most suitable wireless technology for WBANs by using fuzzy logic. Its goal is to select a wireless communication technology available considering the user/application requirements and network conditions. A WBAN is composed of a set of sensors placed in, on, or around human body, which monitors the human body functions and the surrounding environment. In an effort to send sensor readings from human body to medical center or a station, a WBAN needs to stay connected to a local or a wide area network by using various wireless communication technologies. Nowadays, several wireless networking technologies may be utilized in WLANs and/or WANs each of which is capable of sending WBAN sensor readings to the desired destination. Therefore, choosing the best serving wireless communications technology has critical importance to provide quality of service support and cost efficient connections for WBAN users. In this work, we have developed, modeled, and simulated some networking scenarios utilizing our fuzzy logic-based NCN by using OPNET and MATLAB. Besides, we have compared our proposed fuzzy logic based algorithm with widely used RSSI-based AP selection algorithm. The results obtained from the simulations show that the proposed approach provides appropriate outcomes for both the WBAN users and the overall network.

• Journal of Korean Society of Industrial and Systems Engineering
• /
• v.42 no.1
• /
• pp.87-94
• /
• 2019

A wireless sensor network is emerging technology and intelligent wireless communication paradigm that is dynamically aware of its surrounding environment. It is also able to respond to it in order to achieve reliable and efficient communication. The dynamical cognition capability and environmental adaptability rely on organizing dynamical networks effectively. However, optimally clustering the cognitive wireless sensor networks is an NP-complete problem. The objective of this paper is to develop an optimal sensor network design for maximizing the performance. This proposed Ranking Artificial Bee Colony (RABC) is developed based on Artificial Bee Colony (ABC) with ranking strategy. The ranking strategy can make the much better solutions by combining the best solutions so far and add these solutions in the solution population when applying ABC. RABC is designed to adapt to topological changes to any network graph in a time. We can minimize the total energy dissipation of sensors to prolong the lifetime of a network to balance the energy consumption of all nodes with robust optimal solution. Simulation results show that the performance of our proposed RABC is better than those of previous methods (LEACH, LEACH-C, and etc.) in wireless sensor networks. Our proposed method is the best for the 100 node-network example when the Sink node is centrally located.

• Journal of the Korea Society of Computer and Information
• /
• v.28 no.9
• /
• pp.121-128
• /
• 2023

To increase the lifetime of the network in wireless sensor networks, energy harvesting from the surrounding environment or wireless power transfer is being used. In addition, to reduce the energy imbalance and increase the amount of data gathered, a method using mobile sink nodes that visit sensor nodes to gather data has been used. In this paper, we propose a technique to reduce the load on the relay node and collect a lot of data evenly in this environment. In the proposed scheme, sensor nodes construct Minimum Depth Trees (MDTs) considering the network environment and energy, and allocate the data collection amount. Simulation results show that the proposed technique effectively suppresses energy depletion and collects more data compared to existing techniques.

• International Journal of Internet, Broadcasting and Communication
• /
• v.4 no.1
• /
• pp.3-7
• /
• 2012

Traditionally SCADA is connected only in a limited private network. With new technology and facilities, there are also demands of connecting SCADA though the internet. The internet SCADA facility has brought a lot of advantages in terms of control, data viewing and generation. Aside from connecting SCADA to the internet, there are also operators who want to connect their system wirelessly. This can save budget for communication lines. Along with the advantages it brings, are security issues regarding wireless internet SCADA. In this paper, we discuss internet SCADA, its connection through wireless communication and the security issues surrounding it. To answer the security issues, a symmetric-key encryption for internet SCADA is proposed.

• Proceedings of the KIEE Conference
• /
• 2007.04a
• /
• pp.340-342
• /
• 2007

When a system is teleoperated in the indoor environment through the wireless LAN, the communication time delay that is due to the inherent characteristic and surrounding environment is random and unbounded. The time delay has a significant effect on the stability and performance of the teleoperating system. In this paper, we present the method that is the image compression, measuring time delay and switching control-mode corresponding to time delay automatically, to improve stability and performance, and the simple experiment is conducted to demonstrate the feasibility

• Journal of Internet Computing and Services
• /
• v.7 no.5
• /
• pp.33-41
• /
• 2006

Wireless LAN is intrinsically weak in security of transmissions. WPKI (Wireless Public Key Infrastructure) is a well known Method to deal with the security issues in wireless LAN. The authentication required by the method becomes a source of unrellability of the hand-off performance. This paper suggests a solution to overcome the instability while using the WPKI technique, Prior to getting into the next region, a station is provided with the keys of the surrounding regions so that the possible delay problem can be avoided during the actual hand-off time. Thereby the hand-off instability can be solved in the WPKI framework.