Ieee Paper

Joon Heo, Student Member, Choong Seon Hong, Member, IEEE, Seok Bong Kang and Sang Soo Jeon

Abstract — In other to save energy, several countries

recently made laws related to standby power consumption. To success this exertion, we should consider not only power reduction of consumer electronics itself but also efficient automatic control in networked home environment. In this paper, we present a design approach and implementation result of control mechanism for standby power reduction. Proposed mechanism has the Host-Agent based structure and uses the IEEE 802.15.4 based ZigBee protocol for communication and security between Host and Agents. We verified reliability of proposed mechanism and reduction effect of standby power; also, we applied implemented device to scenario which is similar to user living pattern. Experimental results demonstrate that in the proposed mechanism, standby power consumption of Agent which is connected to consumer electronics can be reduced by 203mW.1

Index Terms — Standby Power Reduction, Networked Home, Control Mechanism, ZigBee, Home Automation.

I. INTRODUCTION Standby electricity is the energy consumed by appliances

when they are not performing their main functions or when they are switched off. As more and more appliances are being used in households and offices, their energy consumption during standby periods represent a significant share of the total energy used. Household appliances and office equipments such as televisions (TVs), video recorders, audio players, telephone answering and facsimile machines, computers, printers and copiers contribute to this standby loss which is relatively low, with typical loss per appliance ranging from less than 1W to as much as 25W. According to the IEA (International Energy Agency), on an average, 10% of a total household (OECD) power consumption is being wasted in the form of standby power. Moreover, due to the special characteristics of home network devices such as set top box, xDSL modem, home gateway, PC and TV can all be connected to the external communication system in standby mode; an increase of standby power consumption is expected.

Joon Heo is a Ph.D candidate at the Department of Computer Engineering, Kyung Hee University, South Korea. (e-mail: [email protected])

Dr. Choong Seon Hong is a professor at the Department of Computer Engineering, Kyung Hee University, South Korea. (e-mail: [email protected]). Dr. CS Hong is corresponding author.

Seok Bong Kang is a CEO at the I’ware Inc., Ltd, South Korea. (e-mail: [email protected])

Sang Soo Jeon is a Senior Engineer at the VITZRO SYS Co., Ltd, South Korea. (e-mail: [email protected])

It is apparent that the future market will be dominated by electric/electronic devices with network functions, rather than those devices without network functions. The number of products with standby power consumption is growing rapidly in both quantity and diversity [1][5]. The increasing power consumption makes the environment worse by increasing global carbon dioxide, which is the cause of the greenhouse effect [6]. And a lot of efforts were made to reduce power consumption in the field of hardware, software, and chips [4][7][12].

A home automation system is a collection of networked home appliances. During recent years, a lot of research has been done in this area, and a lot of papers have been published [9][10][11][14][15]. In this paper, a proposed standby power control system consists of a Host and networked Agents. The Host is the brain of this system; various types of Agent which is attached consumer electronics connected to this system communicate between each other through the Host.

ZigBee is a new low rate wireless network standard designed for automation and control network. The standard is aiming to be a low-cost, low-power solution for systems consisting of unsupervised groups of devices in houses, factories and offices. Expected applications for the ZigBee are building automation, security systems, remote control, remote meter reading and computer peripherals. The ZigBee standard utilizes IEEE 802.15.4 standard as radio layer [2][3].

In this paper, we propose a standby power control mechanism in networked home. Proposed mechanism uses the IEEE 802.15.4 based ZigBee communication protocol between Host and Agents for sensing information and standby power control command transmission. Agent acquires the local information such as lighting, power consumption and user motion detection using the various embedded sensors and sends this sensing value to the Host; then, Host compares this sensed value with defined control algorithm and sends the standby power control command to the Agent. This paper is organized as follows. Section 2 explains about related works such as the type of standby power, increment of standby power in recent home environment and low power wireless protocol. Section 3 describes the proposed communication and security modules of control system; this section also explains design approaches of Host and Agent. Implementation results and prototype device are presented in section 4. Section 5 analyzes the preliminary results according to scenarios. Finally, we have given some concluding remarks and future works.

Design and Implementation of Control Mechanism for Standby Power Reduction

J. Heo et al.: Design and Implementation of Control Mechanism for Standby Power Reduction 179

Manuscript received January 15, 2008 0098 3063/08/$20.00 © 2008 IEEE

II. RELATED WORKS

A. Type of Standby Power and Consumption Increment As shown in Table 1, Standby power of many devices can

further be classified into no-load mode, off mode, passive standby mode, active standby mode, and sleep mode. With the current level of technology, 1W objective can be achieved at no-load mode, off mode, and passive standby mode [16].

TABLE Ⅰ

DEFINITION AND TYPES OF STANDBY POWER

Category Description Power Status Products

No Load

State of the power supply when no power is being provided to the rest of the appliances

-

External power supply(DC/AC power supply, phone battery charger)

Off The appliances is switched off and has no capacity

Put-Off TV, VCR, audio, DVD player, PC, monitor, printer

Passive Standby

The appliances is off, but can be powered up remotely

Put-Off TV, VCR, audio, DVD player, Setop box

Active Standby

The appliances is on, but is not providing a primary function

Put-Off Setop box, home network system

Sleep Mode entered after a period inactivity Put-On PC, monitor, printer,

facsimile, scanner A new form of standby power called ‘Active Standby’ is

becoming a reality that we have to face. The emergence of active standby power started with the introduction of set top boxes. It is a power mode where the consumer switches off the power (the consumer thinks the power is switched off completely) but the internal circuit still consumes standby power to wait for external cord/cordless signals. According to previous research [8], in 2020 the increased electricity consumption resulting from networking amounts to around 30% of the present-day consumption in private households in Switzerland. Approximately 1/4 of this is attributable to power consumed in standby and off mode. In 1999, IEA has proposed to reduce the standby power of all electronic products below 1W, the so called ‘1-watt Plan’. Several countries such as US government (2001), Australian government (2002) and Korea government (2004) already announced a national strategy to achieve the 1W standby power target.

B. Low-Power Wireless Protocol The IEEE 802.15.4 wireless standard was developed

specifically for remote monitoring and control. The standard defines transmission and reception on the physical radio channel (PHY), and the channel access, PAN (personal area network) maintenance, and reliable data transport (MAC). ZigBee defines the topology management, MAC management, routing, discovery protocol, security management and includes the 802.15.4 portions. ZigBee is battery operated and designed for the applications that need to transmit small amount of data. As a result the architecture of protocols and

hardware for end devices should be light-weight in order to achieve lower power consumption. The coordinator and routing devices should not be battery powered, as these are designated for transmitting, receiving and as well as the whole network functionality.

The data transfer mechanism depends on the topology. Security and data integrity are key benefits of the ZigBee technology. The ZigBee architecture recognizes two types of devices RFD (Reduced Function Device) and FFD (Full Function Devices). Only the FFD defines the full ZigBee functionality and can become a network coordinator. The RFD has limited resources and does not allow some advanced functions (e.g. routing) as it is a low cost end device solution. Each ZigBee network has a designed FFD that is a network coordinator. The coordinator acts as the administrator and takes care of organization of the network. Typical coordinator has a neighbor table of devices found in the neighborhood. This leads to extended demands on the coordinator device, as it needs more memory and processing power [2][3].

III. PROPOSED MECHANISM In this paper, we propose Host-Agent based structure to

control standby power of consumer electronics effectively; Host and Agent are the two main components. Host manages the entire system and generates standby power control command. While the Agent steer actuator according to control command received from the Host. Possible options of agent position includes

Internal: It can be embedded with the consumer electronics

External: As socket outlet form (e.g. wall type, movement type, button type)

The former option is better from device integration point of view. However, we have followed latter approach as the socket outlet form devices could easily be installed by the users in the real home environment.

The essential goals of proposed mechanism are stated below:

Home automation based control Standby power of Consumer Electronics ≤ 250mW Sensor embedded devices and operation Low power actuator, Device compatibility High reliability of control system

Both Host and Agent have several built in sensors, therefore these devices can acquire the specific sensing information such as user motion, illumination and temperature in home environment. Host receives the sensed information from the Agent and generates standby power control command using the embedded standby power control algorithms and threshold value. After control command reception, Agent isolates or connects the standby power of consumer electronics. In the following subsection, we explain ZigBee ready communication module, detailed function design of Host and Agent.

180 IEEE Transactions on Consumer Electronics, Vol. 54, No. 1, FEBRUARY 2008

A. Host-Agent based Architecture The proposed mechanism uses IEEE 802.15.4[2] based

ZigBee communication protocol for sensing information and control command transmission between Host and Agents. Therefore, we have optimized and applied network and security functions in the implemented devices according to ZigBee specification [3]. Figure 1 shows the concept of proposed control network. The proposed control mechanism has been organized in accordance with tree topology.

Fig. 1. Host-Agent based Standby Power Control

B. Function Design of Host The Host has two major tasks: One is to communicate with

Agents using the ZigBee technology. The other is to determine control commands (standby power isolation or connection) using the sensing information from the Agents. To accomplish these tasks we have defined several modules for the Host e.g. MCU module, sensor module etc. Requirements and responsibilities of MCU module and sensor module are described in Table 2.

TABLE Ⅱ REQUIREMENT OF HOST

Module Requirement

MCU Module

- low power consumption - role of Coordinator (interface with ZigBee module) - standby power control algorithm, - sufficient memory

Sensor Module

- user motion detection - environment condition sensing - reliability of sensing operation

Detailed diagram of Host component is shown in Figure 2.

In this figure, function key and LCD (Liquid Crystal Display) serves as user interface to input the threshold value regarding sensed information and the control scenario of standby power. Therefore, user-defined threshold values can be initialized/adjusted using the function key and LCD. However, we prefer to implement remote controller type user interface in future for user convenience.

Fig. 2. Diagram of Host Components

C. Function Design of Agent Proposed Agent can be connected to consumer electronics

as socket outlet form. To accomplish the tasks of the Agent, we have defined several modules such as power, actuator, sensing and MCU. Requirements and responsibilities of each of the modules are described in Table 3.

TABLE Ⅲ REQUIREMENT OF AGENT

Module Requirement

Power Module

- system voltage supply (12V, 3.3V) - general wall socket size - power consumption less than 0.08Watt

Current Sensing Module

- small size - maintenance of linear type - strength till reliable range

Actuator Module

- strength till reliable range - chattering countermeasure

Sensor Module

- user motion detection - environment condition sensing - reliability of sensing operation

MCU Module

- low power consumption, sufficient memory - interface with ZigBee module - measurement and control ports

Figure 3 shows the block diagram of Agent and relation of

each module. Each module has been designed for minimized power consumption and effectively control of standby power of consumer electronics using the control command.

Fig. 3. Diagram of Agent Components

Modules of the Agent component are described below: a) Power module

Transformer-less type has the disadvantage of surge and EFT (Electric Fast Transient) signal in power line,

J. Heo et al.: Design and Implementation of Control Mechanism for Standby Power Reduction 181

but this type consumes much less current than transformer type in initial no-load power consumption.

Transformer type has the advantages of EMC (Electronic Magnetic Compatibility) and energy efficiency, but this type consumes much more initial current and costs higher than transformer-less type.

Finally after considering about EMC safety, our agent was developed as transformer type.

b) Communication module Agent get the transferred data (Rx, Tx) from the

ZigBee IC (CC2420) as serial communication using the SPI (Serial Peripheral Interface) serial port and external interrupt input port of MCU(MSP430) which is connected to out port of CC2420.

This module was realized wireless communication antenna as PCB (Printed Circuit Board) design and uses patch antenna.

To raise reliability of wireless communication, this module was added as a filter circuit between ZigBee IC (Integrated Circuit) and PCB antenna to prevent noise sensing.

c) Power observation module This module can keep the linearity of current increase

and decrease to flow OP-AMP (Operational Amplifier) throughout CT (Current Transformer).

Detailed measurements are organized using the full wave circuit or amplification circuit according to demands.

d) Sensor module Light and PIR (Passive Infra Red) sensors are used to

detect motion of user. Additionally IR (Infra Red) sensors are used to

recognize remote control for controlling the electric device.

Light sensor acquires regional illumination. Other sensor such as temperature and humidity can be

added in the Agent according to demands. e) Actuator module

Actuator module was designed to focus on the durability about a rated current (AC250V/15A)

The advantage of relay is the guarantee over rated current of durability and simple control method.

As the dual port controlling, Agent can completely cutoff the standby power by Triac which can measure of big capacity.

f) CPU module Agent has the flexible IO-port (Input/Output port) to

control easily. Agent has the basic memory (1M byte RAM and 56k

byte program memory) inside and extension memory (1M byte).

This module was used MSP430 (16bit MCU) to apply ZigBee protocol as communication technology.

This module is used to realize the low current consumption using the 3.3V running and Active/LPM

(Low Power Mode [13]) status; to apply LPM, two interrupt methods to wake up LPM mode were used. One is the external interrupt from communication module especially CC2420, the other is the timer interrupt from embedded Auxiliary Clock (ACLK). Figure 4 shows a flow chart of mode conversion by timer interrupt. Mode conversion by communication also follows same procedure.

LPM: Within short duration of time after communicating with Host (receiving the mode conversion command from Host and sending sensor measurement data), the Agent converts Active mode into LPM mode for relatively longer period.

Start

Agent stops the standby power measurement and sensing

Agent establishes the SR (Special Register)

Agent converts Active mode into LPM

Active Mode

Agent converts LPM into Active mode

Agent starts the standby power measurement and

sensing

End

LPM commandfrom Host with duration

time?

ACLK>=Timeout?

No

No

Yes

Fig. 4. Flowchart of Mode Conversion and Timer Interrupt

Figure 5 shows the layout of the proposed Agent to apply

components as described in Figure 3 to the socket outlet form Agent. The size of designed Agent is suitable to wall socket standard; also for safety, ZCT (Zero-Phase Current Transformer) was applied to agent for measuring isolation of electric leakage in electric application.

Fig. 5. Layout of the Proposed Agent Prototype

IV. IMPLEMENTATION In this section, we present implemented devices (Host and

Agents) according to each designed module and their

182 IEEE Transactions on Consumer Electronics, Vol. 54, No. 1, FEBRUARY 2008

characteristics. Optimized ZigBee module for proposed system has been implemented in the devices. The implemented devices can be applied to real home environment easily without modifying the consumer electronics.

A. Communication and Security Module As we mentioned before, the proposed architecture of this

paper uses IEEE 802.15.4 based ZigBee communication protocol. Therefore, we have implemented and optimized network and security functions at prototype devices according to ZigBee specification [3]. The proposed control architecture has been organized based on tree topology. Requirement functions such as routing, address allocation, encryption/decryption and message authentication have been tested. Implemented security module supports ZigBee security specification such as CCM* algorithm, MAC/NWK layer security, key establishment, message encryption/decryption and message integrity [5].

B. Host Implementation The size of implemented Host is 90mm in diameter and it

can be installed on the ceiling. Basically, it consists of power module, RF/MCU module, PIR sensor, light sensor and USB connector. To accomplish user defined configuration, we can add equipments related to user input such as function key and LCD display. Figure 6 shows the real shape and main module.

Fig. 6. Appearance of Implemented Host

Main characteristic of implemented Host are like below: ⓐ Standby power control application

- Availability of operation ≥ 87% - Communication rate: 250kbps - Communication distance: 30m - Response speed: 0.5 second ⓑ Sensor application - Embedded light sensor, PIR sensor ⓒ 32bit ARM Core in TCC 63 Microprocessor - CC2420 based ZigBee Communication IC

C. Agent Implementation Figure 7 shows the hardware prototype of Agent. The size

of implemented Agent is 46mm in width and 86mm in height. Basically, it consists of power module, RF/MCU module, PIR sensor, light sensor and power actuator.

Fig. 7. The Hardware Prototype of the Agent

Main characteristics of implemented Agent are like below: ⓐ Standby power consumption: 203mW - Fly-Black Power constitution - Unity Power: 3V, 500mA - Low power MCU and ZigBee modules ⓑ Sensor application - Light sensor, PIR sensor ⓒ Leakage current detection Module - Passive leakage interception switch - Minimum detection current: 5mA

ⓓ General wall socket size

Agent has been implemented as three types (socket type outlet, movement type outlet and button type switch). Figure 8 shows the appearance of wall socket type outlet and movement type outlet. Each type can be used according to user demands.

Fig. 8. Appearance of Implemented Agent

V. PRELIMINARY RESULTS AND ANALYSIS Measurement of standby consumption has been performed

using two methods. One is to measure power consumption when Agent is in Active or in LPM mode. The other is to measure standby power according to scenarios which is related to user living patterns. The results of first method are shown in Table 4 and Figure 9.

J. Heo et al.: Design and Implementation of Control Mechanism for Standby Power Reduction 183

TABLE Ⅳ POWER CONSUMPTION OF AGENT ACCORDING TO MODE Section Voltage Active Mode LPM

RF 3.0 V 30 mW ≒ 0 mW MPU 3.0 V 60 mW ≒ 0 mW

Current Sensor 3.0 V ≒ 0 mW ≒ 0 mW

Light Sensor 3.0 V ≒ 0 mW ≒ 0 mW

Actuator 3.0 V ≒ 0 mW ≒ 0 mW Power Supply 3.0 V 110 mW < 80mW

Total Consumption 3.0 V 203mW < 80 mW

Fig. 9. Comparison of Power Consumption between Active and LPM Power consumption of Agent to convert into LPM mode is

nearly 0W because this action is performed according to command from Host. Basically, power supply is the SMPS (Switch Mode Power Supplies) mode. When voltage was descent from 220V to 3.3V, there is power loss which is less than 80mW. In Figure 9, mode of Agent was changed by LPM command from the Host, timer interrupt and external interrupt from the communication module.

To prove the necessity and the efficiency of the proposed control mechanism, we have made an experiment on standby power control according to scenarios using the implemented prototype devices. Table 5 explains the test scenarios according to sensing information and Figure 10 shows the real testbed environment. For example, when user turn off the computer and go out the room according to scenario 4, CT sensor of Agent 2 acquires the current power value (less than 5W) and PIR sensor of Agent 3 detects the user motion (no user in the room). After receiving these sensing values from Agent 2 and Agent 3, Host compares these values with control algorithm and sends the standby power isolation command to the Agent 2. The distance between Host on the ceiling and Agents is about 6m. Used Agents of this test include CT (Current Transformer) sensor, ZCT (Zero-Phase Current Transformer) sensor and PhotoDiode (Light) sensor; and optionally these agents can include PIR (Passive InfraRed) sensors. During these tests, the average power consumption at the Host is less than 2W. As a result, the Agent 2 consumes 203mW when it is in Active state, and, 80mW in LPM state; when we do not use proposed reduction mechanism, the standby consumption of monitor which is connected Agent 2

is more than 4W. Similar standby power consumption value has been estimated at every Agent.

TABLE Ⅴ TEST SCENARIOS ACCORDING TO SENSING INFORMATION

Scenario Sensing Information Controlled Agent 1 Indoor lighting value Agent 1 (socket type outlet) 2 Cooperation with Agents Agent 3 and 4 (movement type) 3 PIR sensing value Agent 5 (button type switch) 4 PIR and CT value Agent 2 (socket type outlet)

Fig. 10. Standby Power Control Testbed using the Prototype Device

VI. CONCLUSION As consumer electronics in home are networked, the total

consumption of standby power will greatly increase. The power reduction technology of device itself has limitation. Therefore networked home automation system for standby power reduction should be developed. In this paper, we proposed a Host-Agent based standby power control mechanism. The main role of the Host is to manage entire control system and to generate control command. Agent sends the sensing information to the Host and controls standby power. According to proposed scheme, we implemented two kinds of hardware components, a Host and several Agents. Experimental results demonstrate that in the proposed mechanism, standby power consumption of consumer electronics can be reduced. As the future work, we will analyze the mechanism according to various scenarios in home network and enhance the correctness of the proposed system according to user living scenarios. We are currently developing remote controller to apply in our proposed mechanism for a better user interface.

REFERENCES [1] J. Heo, CS. Hong, SB. Kang, SS. Jeon, “Standby Power Control

Architecture in Context-Aware Home Networks,” Lecture Note in Computer Science, vol. 4773, pp. 515-518, OCTOBER 2007.

[2] IEEE Std. 802.15.4 Wireless Medium Access Control (MAC) and Physical Layer (PHY) Specification for Low-Rate Wireless Personal Area Networks, MAY 2003.

[3] ZigBee Alliance, ZigBee Specification Version 1.0, DECEMBER 2004. from http://www.zigbee.org

[4] Calboun B.H., Chandrakasan A.P., “Standby Power Reduction Using Scaling and Canary Flip-Flop Structures,” IEEE Journal of Solid-State Circuits, Vol. 39, No. 9, pp. 1504-1511, SEPTEMBER 2004.

[5] J. Heo, CS. Hong, SB. Kang, SS. Jeon, “Wireless Home Network Control Mechanism for Standby Power Reduction,” Proceedings of WINSYS 2007, pp. 70-75, JULY 2007.

[6] Mcgarry L., “The Standby Power Challenge,” Proceedings of IEEE AGEC 2004, pp. 56-62, JANUARY 2004.

184 IEEE Transactions on Consumer Electronics, Vol. 54, No. 1, FEBRUARY 2008

[7] Watanabe K., Ise M., Onoye T., Niwamoto H., Keshi I., “An Energy-

efficient Architecture of Wireless Home Network Based on MAC Broadcast and Transmission Power Control,” Proceedings of IEEE ICCE 2007, pp. 1-2, JANUARY 2007.

[8] Aebischer B. and A. Huser, “Networking in private households. Impacts on electricity consumption,” Report for the Swiss Federal Office of Energy, NOVEMBER 2000.

[9] Zhaohui Ye, Yindong Ji and Shiyuan Yang, “Home Automation Network Supporting Pulg-and-Play,” IEEE Transaction on Consumer Electronics, Vol. 50, No. 1, pp.173-179, FEBRUARY 2004.

[10] Kyung Chang Lee and Hong Hee Lee, “Network-based Fire-Detection System via Controller Area Network for Smart Home Automation,” IEEE Transaction on Consumer Electronics, Vol. 50, No. 4, pp.1093-1100, NOVEMBER 2004.

[11] Soo Hwan Choi, Byung Kug Kim, Jinwoo Park, Chul Hee Kang and Doo Seop Eom, “An Implementation of Wireless Sensor Network for Security System using Bluetooth,” IEEE Transaction on Consumer Electronics, Vol. 50, No. 1, pp.236-244, FEBRUARY 2004.

[12] Jinsoo Han, Intark Han and Kwang Roh Park, “Service-Oriented Power Management for an Integrated Multi-Function Home Server,” IEEE Transaction on Consumer Electronics, Vol. 53, No. 1, pp.204-208, FEBRUARY 2007.

[13] Andreas Dannenberg, “HDQ Prototol Implementation with MSP430,” TEXAS INSTRUMENTS Application Report, SLAA196, FEBRUARY 2004.

[14] Jung Won Kang, Soon Heung Jung, Jae Gon Kim and Jin Woo Hong, “Development of QoS-Aware Ubiquitous Context Access (UCA) Testbed,” IEEE Transaction on Consumer Electronics, Vol. 53, No. 1, pp.197-203, FEBRUARY 2007.

[15] Xie Li and Wenjun Zhang, “The Design and Implementation of Home Network System Using OSGi Compliant Middleware,” IEEE Transaction on Consumer Electronics, Vol. 50, No. 2, pp.528-534, MAY 2004.

[16] YR. Kim, “KOREA 1W Policy,” Standby Power Conference, Nov. 2006.

Joon Heo received the B.S. and M.S. degree in Department of Computer Engineering from Kyung Hee University, South Korea, in 2002 and 2004. Since 2004, he was working toward his Ph.D degree and currently he is a Ph.D candidate in Department of Computer Engineering at Kyung Hee University. He is a student member of IEEE, KISS, KIPS and KICS. His research interests are wireless sensor network, network security

and power line communication.

Choong Seon Hong received his B.S. and M.S. degrees in electronics engineering from Kyung Hee University, Seoul, Korea, in 1983, 1985, respectively. In 1988 he joined KT, where he worked on Broadband Networks as a member of the technical staff. From Sept. 1993, he joined Keio University, Japan. He received the Ph.D. degree at Keio University in March 1997. He had worked

for the Telecommunications Network Lab, KT as a senior member of technical staff and as a director of the networking research team until August 1999. Since September 1999, he has worked as a professor of the School of Electronics and Information, Kyung Hee University. His research interests include Ad hoc Networks, Network Security and Network Management. He is a Member of IEEE, IEICE, IPSJ, KISS, KIPS, and KICS.

Seok Bong Kang received the B.S and M.S degrees in dept of electronic engineering form Kyung Hee University, Seoul Korea, in1983 and 1988, respectively. In 1985 he joined Samsung Electronics, where he worked on network appliances for twenty years as a R&D project leader and manager. He established IWARE. Co., Ltd in 2004. The major items of this company are sensor

network and SoC applications. His company is carrying out several governments funded R&D projects. The research and development for the reduction of power consumption of appliances that is funded by KEMCO is one of those R&D projects.

Sang Soo Jeon received B.Sc. in dept. of control and instrumentation engineering from Kwangwoon university, Seoul, Korea, in 1998. He joined KIST (Korea Institute of Science and Technology) in 1998, His work in KIST was to design a basic-system which can control motor by processing data acquired and sensed by means of encoders, sensors and so on. Since 2000, he has been

developed intelligent power system at the VITZRO SYS Co., Ltd

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