• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.4
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• pp.664-673
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• 2018

The industrial control system (ICS) has operated as a closed network in the past, but it has recently been linked to information and communications services and has been causing damage due to cyber attacks. As a countermeasure, the Information Communication Infrastructure Protection Act was enacted, but it cannot be applied to various real control environments because there is only a one-way policy-from a control network to a business network. In addition, IEC62443 defines an industrial control system reference model as an international standard, and suggests an area security model using a firewall. However, there is a limit to linking an industrial control network, operating as a closed network, to an external network only through a firewall. In this paper, we analyze the security model and research trends of the industrial control system at home and abroad, and propose an industrial control system security model that can be applied to the actual interworking environments of various domestic industrial control networks. Also, we analyze the security of firewalls, industrial firewalls, network connection equipment, and one-way transmission systems. Through a domestic case and policy comparison, it is confirmed that security is improved. In the era of the fourth industrial revolution, the proposed security model can be applied to security management measures for various industrial control fields, such as smart factories, smart cars, and smart plants.

• Proceedings of the IEEK Conference
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• 2005.11a
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• pp.1023-1026
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• 2005

In the ubiquitous computing environment, an intelligent vehicle is defined as a sensor node with a capability of intelligence and communication in a wire and wireless network space. To make it real, a lot of problems should be addressed in the aspect of vehicle mobility, in-vehicle communication, common service platform and the connection of heterogeneous networks to provide a driver with several intelligent information services beyond the time and space. In this paper, we present an intelligent information system for managing in-vehicle sensor network and a vehicle gateway for connecting the external networks. The in-vehicle sensor network connected with several sensor nodes is used to collect sensor data and control the vehicle based on CAN protocol. Each sensor node is equipped with a reusable modular node architecture, which contains a common CAN stack, a message manager and an event handler. The vehicle gateway makes vehicle control and diagnosis from a remote host possible by connecting the in-vehicle sensor network with an external network. Specifically, it gives an access to the external mobile communication network such as CDMA. Some experiments was made to find out how long it takes to communicate between a vehicle's intelligent information system and an external server in the various environment. The results show that the average response time amounts to 776ms at fixed place, 707ms at rural area and 910ms at urban area.

• Journal of Biosystems Engineering
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• v.42 no.1
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• pp.23-43
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• 2017

Purpose: As application-specific wireless sensor networks are gaining popularity, this paper discusses the development and field performance of the GHAN, a greenhouse area network system to monitor, control, and access greenhouse microenvironments. GHAN, which is an upgraded system, has many new functions. It is an intelligent wireless sensor and actuator network (WSAN) system for next-generation greenhouses, which enhances the state of the art of greenhouse automation systems and helps growers by providing them valuable information not available otherwise. Apart from providing online spatial and temporal monitoring of the greenhouse microclimate, GHAN has a modified vapor pressure deficit (VPD) fuzzy controller with an adaptive-selective mechanism that provides better control of the greenhouse crop VPD with energy optimization. Using the latest soil-matrix potential sensors, the GHAN system also ascertains when, where, and how much to irrigate and spatially manages the irrigation schedule within the greenhouse grids. Further, given the need to understand the microclimate control dynamics of a greenhouse during the crop season or a specific time, a statistical assessment tool to estimate the degree of optimality and spatial variability is proposed and implemented. Methods: Apart from the development work, the system was field-tested in a commercial greenhouse situated in the region of Punjab, India, under different outside weather conditions for a long period of time. Conclusions: Day results of the greenhouse microclimate control dynamics were recorded and analyzed, and they proved the successful operation of the system in keeping the greenhouse climate optimal and uniform most of the time, with high control performance.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.7 no.8
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• pp.1805-1824
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• 2013

Recently, the use of wireless body area networks (WBAN) has been increasing rapidly in medical healthcare applications. WBANs consist of smart nodes that can be used to sense and transmit vital data such as heart rate, temperature and ECG from a human body to a medical centre. WBANs depend on limited resources such as energy and bandwidth. In order to utilise these resources efficiently, a very well organized medium access control (MAC) protocol must be considered. In this paper, a new, adaptive and energy-efficient MAC protocol, entitled isMAC, is proposed for WBANs. The proposed MAC is based on multi-channel communication and aims to prolong the network lifetime by effectively employing (i) a collision prevention mechanism, (ii) a coordinator node (WCN) selection algorithm and (iii) a transmission power adjustment approach. The isMAC protocol has been developed and modelled, by using OPNET Modeler simulation software. It is based on a networking scenario that requires especially high data rates such as ECG, for performance evaluation purposes. Packet delay, network throughput and energy consumption have been chosen as performance metrics. The comparison between the simulation results of isMAC and classical IEEE 802.15.4 (ZigBee) protocol shows that isMAC significantly outperforms IEEE 802.15.4 in terms of packet delay, throughput and energy consumption.

• Journal of information and communication convergence engineering
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• v.11 no.1
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• pp.7-11
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• 2013

Wearable computer systems use the wireless universal serial bus (WUSB), which refers to USB technology that is merged with WiMedia physical layer and medium access control layer (PHY/MAC) technical specifications. WUSB can be applied to wireless personal area network (WPAN) applications as well as wired USB applications such as PAN. WUSB specifications have defined high-speed connections between a WUSB host and WUSB devices for compatibility with USB 2.0 specifications. In this paper, we focus on an integrated system with a WUSB over an IEEE 802.15.6 wireless body area network (WBAN) for wireless wearable computer systems. Due to the portable and wearable nature of wearable computer systems, the WUSB over IEEE 802.15.6 hierarchical medium access control (MAC) protocol has to support power saving operations and integrate WUSB transactions with WBAN traffic efficiently. In this paper, we propose a low-power hibernation technique (LHT) for WUSB over IEEE 802.15.6 hierarchical MAC to improve its energy efficiency. Simulation results show that the LHT also integrates WUSB transactions and WBAN traffic efficiently while it achieves high energy efficiency.

• Proceedings of the KIEE Conference
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• 1999.07c
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• pp.1035-1038
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• 1999

To improve the damping of all poorly damped oscillation modes, a control strategy of Static Synchronous Series Compensator (SSSC) based on energy method is presented in this Paper As a synchronous voltage-sourced inverter, SSSC is used to provide controllable series compensation. SSSC can provide controllable compensating voltage over an identical capacitive and inductive range. The damping effect of control strategy based on energy function is robustness with respect to loading condition, fault location and network configuration. Furthermore, the control inputs are based on local signals. In two area system, the effect of damping inter-area mode oscillation is demonstrated by the robust control strategy of SSSC.

• Smart Media Journal
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• v.6 no.4
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• pp.65-71
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• 2017

In this paper, we propose a design method for the construction of LTE-based small unmanned aerial vehicle control system to quickly and reliably collect multiple small unmanned aerial vehicle position information simultaneously flying all over the country. In particular, the main requirements are the network (N/W), hardware (H/ W), software(SW), Database(DB), development architecture, and business needs. To satisfy these requirements, N/W, H/W, SW, DB design, and architectural design plan were suggested regarding the design requirements of a small UAV system. To effectively control the small unmanned multi-party system in the system design, the architecture is divided into the front-end service area and the back-end service area according to the function and role of the unit system. In the front-end service area that grasps and controls the position and state of small unmanned aerial vehicles (UAVs), we have studied the design part that can be expanded to N through TCP/IP network by applying Client PC method.

• Journal of Communications and Networks
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• v.8 no.3
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• pp.297-305
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• 2006

High-rate wireless personal area network (HR-WPAN) has been standardized by the IEEE 802.15.3 task group (TG). To support multimedia services, the IEEE 802.15.3 TG adopts a time-slotted medium access control (MAC) protocol controlled by a central device. In the time division multiple access (TDMA)-based wireless packet networks, the packet scheduling algorithm plays a key role in quality of service (QoS) provisioning for multimedia services. In this paper, we propose an adaptive cross-layer packet scheduling method for the TDMA-based HR-WPAN. Physical channel conditions, MAC protocol, link layer status, random traffic arrival, and QoS requirement are taken into consideration by the proposed packet scheduling method. Performance evaluations are carried out through extensive simulations and significant performance enhancements are observed. Furthermore, the performance of the proposed scheme remains stable regardless of the variable system parameters such as the number of devices (DEVs) and delay bound.

• ETRI Journal
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• v.41 no.4
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• pp.465-472
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• 2019

The major challenge in wireless body area networks (WBAN) is setting up a protected communication between data consumers and a body area network controller while meeting the security and privacy requirements. This paper proposes efficient and secure data communication in WBANs using a Twofish symmetric algorithm and ciphertext-policy attribute-based encryption with constant size ciphertext; in addition, the proposed scheme incorporates policy updating to update access policies. To the best of the author's knowledge, policy updating in WBAN has not been studied in earlier works. The proposed scheme is evaluated in terms of message size, energy consumption, and computation cost, and the results are compared with those of existing schemes. The result shows that the proposed method can achieve higher efficiency than conventional methods.

• JSTS:Journal of Semiconductor Technology and Science
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• v.6 no.4
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• pp.299-312
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• 2006

This paper presents the results of a novel test structure for process control monitor for uncooled IR detector technology of microbolometer arrays. The proposed test structure is based on resistive network configuration. The theoretical model for resistance of this network has been developed using 'Compensation' and 'Superposition' network theorems. The theoretical results of proposed resistive network have been verified by wired hardware testing as well as using an actual 16x16 networked bolometer array. The proposed structure uses simple two-level metal process and is easy to integrate with standard CMOS process line. The proposed structure can imitate the performance of actual fabricated version of area array closely and it uses only 32 pins instead of 512 using conventional method for a $16{\times}16$ array. Further, it has been demonstrated that the defective or faulty elements can be identified vividly using extraction matrix, whose values are quite similar(within the error of 0.1%), which verifies the algorithm in small variation case(${\sim}1%$ variation). For example, an element, intentionally damaged electrically, has been shown to have the difference magnitude much higher than rest of the elements(1.45 a.u. as compared to ${\sim}$ 0.25 a.u. of others), confirming that it is defective. Further, for the devices having non-uniformity ${\leq}$ 10%, both the actual non-uniformity and faults are predicted well. Finally, using our analysis, we have been able to grade(pass or fail) 60 actual devices based on quantitative estimation of non-uniformity ranging from ＜ 5% to ＞ 20%. Additionally, we have been able to identify the number of bad elements ranging from 0 to ＞ 15 in above devices.