• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.7
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• pp.1608-1613
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• 2009

All kinds of equipment which used an embedded system is developed, and these are used as to an actual life in developments regarding an embedded field in a lot of sections. Also, we can collect data from all kinds of sensors through wireless sensor networks, look by real time data collected could be brought if only through embedded system. In this paper we present a plan which improve the capabilities of embedded system only act as a gateway by installing embedded database in an embedded system for the sensing data management that was transmitted by radio from sensor nodes. In other words, by installing an embedded database to store and manage data by sensing data can be reduced the transmission frequency to communicate with a host and by performing the filtering program in embedded system and then by transmitting only valid data to the host can be increase the reliability of the analysis results based on data collected.

• The KIPS Transactions:PartC
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• v.15C no.4
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• pp.303-310
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• 2008

To increase the lifetime of ad-hoc networks, a ratio of energy consumption for each node should be kept constant by equally distributing network traffic loads into all of the nodes. In this paper, we propose a modified AODV routing protocol to determine a possible route by considering a remaining battery capacity of a node and the degree of its usage. In addition, to reduce the amount of energy consumption during the path rediscovery process due to the huge amount of the AODV control messages the limited number of possible routes are stored into a routing table of a source node. When some links of a route fail, another possible path can be looked up in the table before the route discovery process should be initiated. We have tested our proposed method with a conventional AODV and a MMBCR method which is one of the power-efficient energy routing protocols based on the three performance metrics, i.e., the total remaining battery capacity, network lifetime and the ratio of data packets received by the destination node to compare their performance.

• The KIPS Transactions:PartD
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• v.15D no.5
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• pp.599-608
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• 2008

Advanced wireless network and sensor technologies are capable of collecting information such as temperature, humidity, weight, and location about objects at real time in logistics area. Besides, users want to be notified of contextual information about interest of objects whenever they want it and wherever they want it. To satisfy these requirements, applications should collect and analyze contextual information at real time, and must support a service that can notify it to wanted users. Event-based service is one of the way to satisfy these requirement of users. In this paper, we design an event notification system focused on location- and RFID-based logistics area. To do this, we present XML-based event expression model, ECA-based profile definition model, and an algorithm that has high scalability by distinguishing event filtering in two steps. Based on these designs, our implemented system can apply to not only logistics area but also intelligent traffic control system based on RFID or GPS devices.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.2
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• pp.349-353
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• 2016

The purpose of this study was to investigate possible age differences in the attenuation of acceleration in the upper body (from pelvis through shoulder to head) during fast walking. Thirty young and 29 elderly subjects participated in this study. Wireless acceleration sensors were attached on head, shoulder, and pelvis. Subjects performed two trials of fast walking on a treadmill, where the fast speed was defined as 1.5 times of the comfortable speed. Root-mean-squared (RMS) accelerations of each axis were compared with age group and sensor position as independent factors. In the AP direction, the pelvis acceleration was greater in the young and the shoulder-to-head attenuation was also greater in the young (p<0.001), so that the head acceleration was comparable between age groups (p=0.581). In the ML direction, the pelvis acceleration was greater in the young and also the pelvis-to-shoulder attenuation was greater in the young (p<0.001), so that the head acceleration was greater in the elderly group (p<0.001). Insufficient attenuation ML acceleration in the elderly resulting in the greater acceleration in the head may deteriorate the balance control which utilize feedback signals from the sensory organs in head, e.g., vestibular and visual systems.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.11
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• pp.2576-2583
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• 2015

In a full-duplex (FD) wireless cellular network, uplink (UL) users induce the severe inter-user interference to downlink (DL) users. Therefore, a user scheduling that makes a pair of DL user and UL user to use the same radio resource simultaneously influences the system performances significantly. In this paper, we first formulate an optimization problem for user scheduling to minimize the occurrence of outage, aiming to guarantee the quality of service of users, and then we propose a suboptimal user scheduling algorithm with low complexity. The proposed scheduling algorithm is designed in a way where the DL user with a worse signal quality has a higher priority to choose its UL user that causes less interference. Simulation results show that the FD system using the proposed user scheduling algorithm achieves the optimal performance and significantly decreases the outage probability compared with the conventional half-duplex cellular system.

• Journal of Information Technology Services
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• v.14 no.4
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• pp.257-267
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• 2015

We propose a vehicle-mounted, location-aware mobile digital signage system that can be used for public transportation through mobile communication. This paper proposes the installations of the LED display panels at the backside of the bus., which display traffic information to cars behind the bus. Information to be displayed would include, but is not limited to, road information, public commercials and private commercials. We propose the system architecture and further implement the prototype of mobile digital signage system for demonstration. The system is based on the Client-Server system. Each bus has a client terminal which detects the current location by a GPS receiver and sends its location information to the server using mobile communication function. The terminal device receives advertisements and traffic information from the server and displays it to the large LCD or LED panel installed at the inside and outside of the bus. We use the Android smartphone as a client system, which inherently equipped with GPS and mobile communication function. GPS detects the location of bus and reports its geo-location data to the traffic information center server via a wireless communication network. On the server side, we developed a specially designed control server, where it communicates with the other traffic information center and updates and manages the databases contents being displayed by each position. The server contains location dependent variable information and returns selected information back to the vehicle in real time. Spatial database is used to process location based data. Server system periodically receives the real time traffic information from the road information center database. And it process the information by bus location and bus line number. In this paper, we propose a mobile digital signage service and explain the system implementation of this service.

• Journal of Information Processing Systems
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• v.13 no.5
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• pp.1229-1242
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• 2017

In this paper, an interference aware distributed multi-channel MAC (IDMMAC) protocol is proposed for wireless sensor and actor networks (WSANs). The WSAN consists of a huge number of sensors and ample amount of actors. Hence, in the IDMMAC protocol a lightweight channel selection mechanism is proposed to enhance the sensor's lifetime. The IDMMAC protocol divides the beacon interval into two phases (i.e., the ad-hoc traffic indication message (ATIM) window phase and data transmission phase). When a sensor wants to transmit event information to the actor, it negotiates the maximum packet reception ratio (PRR) and the capacity channel in the ATIM window with its 1-hop sensors. The channel negotiation takes place via a control channel. To improve the packet delivery ratio of the IDMMAC protocol, each actor selects a backup cluster head (BCH) from its cluster members. The BCH is elected based on its residual energy and node degree. The BCH selection phase takes place whenever an actor wants to perform actions in the event area or it leaves the cluster to help a neighbor actor. Furthermore, an interference and throughput aware multi-channel MAC protocol is also proposed for actor-actor coordination. An actor selects a minimum interference and maximum throughput channel among the available channels to communicate with the destination actor. The performance of the proposed IDMMAC protocol is analyzed using standard network parameters, such as packet delivery ratio, end-to-end delay, and energy dissipation, in the network. The obtained simulation results indicate that the IDMMAC protocol performs well compared to the existing MAC protocols.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.2
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• pp.267-276
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• 2009

Nowadays, numerous of valuable internet services are available not only for personal computer but also for mobile appliances in wireless network environment. Therefore, as the amount of contents is increased for those services, the storage limitation on mobile devices has became a significant issue. In this paper, we present a new block-level storage network protocol, iATA (Internet Advanced Technology Attachment) as a solution to the above problem. iATA is designed to transport ATA block-level data and command over the ubiquitous TCP/IP network. With iATA, a mobile appliance is able to access and control the ATA storage devices natively through network from anywhere and at anytime as if the storage devices is attached locally. We describe the concepts, design and diverse consideration of iATA protocol. Based on the benchmark experiments and application exploitation, we strongly believe that iATA as a light-weight protocol is efficient and cost-effective to be used as a storage network protocol on a resource limited device that utilizes common-off-the-shelf storage hardware and existing IP infrastructure.

• Journal of the Korean Association of Geographic Information Studies
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• v.12 no.4
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• pp.158-168
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• 2009

As nation and society progresses, urban ground facilities and their management system get more complicated and the cost and effort to control the system efficiently grows exponentially. This study suggests to the deployment method of a sensor node by Wireless Sensor Network for controling the Urban Ground Facilities of National Facilities. First, we achieve the management facilities and method using the first analysis and then make the coverage of sensing and then set up the Sensor Node in Urban Ground Facilities. Second, we propose the solution way of repetition by the second analysis. And, we embody the GIS program by Digital Map and this method, we improve the reality by overlapping an aerial photo. Also we make an experience on the sensor node allocation using making program. we can remove the repetition sensor node about 50%, and we can confirm that the sensor nodes are evenly distributed on the road.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.11 no.5
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• pp.889-896
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• 2007

Advances in wireless networking, micro-fabrication and integration, and embedded microprocessors have enabled a new generation of massive-scale sensor networks. Because each sensor node is limited in size and capacity, it is very important to design a new simple and energy efficient protocol. Among conventional sensor networks' routing protocols, the directed diffusion scheme is widely blown because of its simplicity. This scheme, however, has a defect in that sending interest and exploratory data messages while setting connection paths consumes much energy because of its flooding scheme. Therefore, this paper proposes a new sensor network routing protocol, called sequenced directed diffusion with a threshold control, which compromises the conventional directed diffusion scheme's defect and offers an energy efficient routing idea. With a computer simulation, its performance is evaluated and compared to the conventional directed diffusion scheme. Numerical results show that the proposed scheme offers energy efficiency while routing packets, and resolves ill-balanced energy consumption among sensor nodes.