• Journal of the Korea Society of Computer and Information
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• v.18 no.8
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• pp.105-111
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• 2013

This paper presents a virtual sensor system that is an effective method to test application software of smart sensors. The common way of testing sensor application is to build a test board, connect sensors to the board, and test sensor applications on the board with sensor's measurements as inputs. The problem of testing sensor application software with sensor's measurements as inputs is the restriction of test data. In other words, software testers cannot manipulate test data, because test data is generated by sensors. To solve this problem a virtual sensor system is presented in this paper. The virtual sensor system enables software testers to manipulate measurements of sensors. In the virtual sensor system, generation of virtual sensors comprises three stages - sensor selection, sensor characterization, and determination of output patterns. Sensor's measurements that can be manipulated through the virtual sensor system make the process of testing efficient. To show the usefulness of our virtual sensor system, it is applied to sensor applications in Android platform and the result of experiments is shown.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1997.10a
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• pp.48-53
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• 1997

The objective of this paper is to present the development and application of interface software between robot and F/T sensor for force control. The interface software for among the robot controller, F/T sensor, and host PC is based on interrupt-driven method. To show the suitability of developed interface software, writing-task is performed in real time using F/T sensor that mounts on the wrist of the robot and Scara type 4-axis robot.

• IEMEK Journal of Embedded Systems and Applications
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• v.2 no.4
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• pp.242-250
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• 2007

Wireless sensor networks are subject to highly heterogeneous system requirements in terms of their functionality and performance due to their broad application areas. Though the heterogeneity hinders the opportunity of developing a single universal platform for sensor networks, efforts to provide uniform, inter-operable and scalable ones for sensor networks are still essential for the growth of the industry as well as their technological advance. As a part of our work to develop such a robust platform, this paper presents the software architecture for sensor nodes with focus on our sensor node operating system and its configuration methodology. Addressing principle issues in its design space which includes programming, execution, task scheduling and software layer models, our architecture is highly reconfigurable with respect to system resources and functional requirements and also highly efficient in supporting multi-threading under small system resources.

• IEMEK Journal of Embedded Systems and Applications
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• v.9 no.4
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• pp.245-251
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• 2014

Wireless Sensor Networks(WSNs) are applied to many monitoring applications. Present sensor nodes can perform many functions at the same time and contain complex software. During the lifetime of sensor nodes, they are required to reprogram their software because of their new functions, software, software bug fixes. The nodes are inaccessible physically or it is very difficult to upgrade their software by one by one. To upgrade the software of sensor nodes in WSNs remotely, this paper presents an energy efficient method by selecting an optimal relay node. The CHR(Cluster Head Relay) method is compared with SPIN and RANDOM method. Three methods are simulated in NS-2 with the same environmental parameters. Simulation results show that CHR shows faster update time and less power consumption compared with other two methods.

• The KIPS Transactions:PartC
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• v.15C no.1
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• pp.9-18
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• 2008

Prevention of attacks being made through program modification in sensor nodes is one of the important security issues. The software-based attestation technology that verifies the running code by checking whether it is modified or not in sensor nodes is being used to solve the attack problem. However, the current software-based attestation techniques are not appropriate in sensor networks because not only they are targeting static networks that member nodes does not move, but also they lacks consideration on the environment that the trusted verifier may not exist. This paper proposes a mutual attestation protocol that is suitable for sensor networks by using SWATT(Software-based ATTestation) technique. In the proposed protocol, sensor nodes periodically notify its membership to neighbor nodes and carry out mutual attestation procedure with neighbor nodes by using SWATT technique. With the proposed protocol, verification device detects the sensor nodes compromised by malicious attacks in the sensor network environments without trusted verifier and the sensor networks can be composed of only the verified nodes.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.26 no.1
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• pp.7-14
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• 2022

Sensor Registry System (SRS) has been devised for maintaining semantic interoperability of data on heterogeneous sensor networks. SRS measures the connectability of the mobile device to ambient sensors based on positions and only provides metadata of sensors that may be successfully connected. The step of identifying the ambient sensors which can be successfully connected is called sensor filtering. Improving the performance of sensor filtering is one of the core issues of SRS research. In reality, GPS sometimes shows the wrong position and thus leads to failed sensor filtering. Therefore, this paper proposes a new sensor filtering strategy using geographical embedding and neural network-based path prediction. This paper also evaluates the service provision rate with the Monte Carlo approach. The empirical study shows that the proposed method can compensate for position abnormalities and is an effective model for sensor filtering in SRS.

• IEMEK Journal of Embedded Systems and Applications
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• v.4 no.3
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• pp.103-111
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• 2009

Software update has been regarded as one of fundamental functions in wireless sensor networks. It can disseminate a delta-image between a current software image operating on a sensor node and its new image in order to reduce an update image(transmission data) size, resultantly saving energy. In addition, code-banking capability of micro-controllers can decrease the update image size. In order to maximize the efficiency of the software update, the proposed scheme exploits both the delta-image and the code-banking at the same time. Besides, it additionally delivers a recovery delta-image to properly handle abnormal conditions, such as message corruptions and unexpected power-off during the update.

• ETRI Journal
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• v.30 no.1
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• pp.47-58
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• 2008

In sensor networks, analyzing power consumption before actual deployment is crucial for maximizing service lifetime. This paper proposes an instruction-level power estimator (IPEN) for sensor networks. IPEN is an accurate and fine grain power estimation tool, using an instruction-level simulator. It is independent of the operating system, so many different kinds of sensor node software can be simulated for estimation. We have developed the power model of a Micaz-compatible mote. The power consumption of the ATmega128L microcontroller is modeled with the base energy cost and the instruction overheads. The CC2420 communication component and other peripherals are modeled according to their operation states. The energy consumption estimation module profiles peripheral accesses and function calls while an application is running. IPEN has shown excellent power estimation accuracy, with less than 5% estimation error compared to real sensor network implementation. With IPEN's high precision instruction-level energy prediction, users can accurately estimate a sensor network's energy consumption and achieve fine-grained optimization of their software.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.6 no.6
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• pp.1546-1564
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• 2012

Pattern-based query processing has not attracted much attention in wireless sensor network though its counterpart has been studied extensively in data stream. The methods used for data stream usually consume large memory and much energy. This conflicts with the fact that wireless sensor networks are heavily constrained by their hardware resources. In this paper, we use piece wise representation to represent sensor nodes' collected data to save sensor nodes' memory and to reduce the energy consumption for query. After getting data stream's and patterns' approximated line segments, we record each line's slope. We do similar matching on slope sequences. We compute the dynamic time warping distance between slope sequences. If the distance is less than user defined threshold, we say that the subsequence is similar to the pattern. We do experiments on STM32W108 processor to evaluate our strategy's performance compared with naive method. The results show that our strategy's matching precision is less than that of naive method, but our method's energy consumption is much better than that of naive approach. The strategy proposed in this paper can be used in wireless sensor network to process pattern-based queries.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.8 no.1
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• pp.123-144
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• 2014

Wireless sensor networks are generally deployed for specific applications to accomplish certain objectives over a period of time. To fulfill these objectives, it is crucial that the sensor network continues to function for a long time, even if some of its nodes become faulty. Energy efficiency and fault tolerance are undoubtedly the most crucial requirements for the design of an information extraction protocol for any sensor network application. However, most existing software agent based information extraction protocols are incapable of satisfying these requirements because of static agent itineraries and large agent sizes. This paper proposes an Information Extraction protocol based on Multiple software Agents with Dynamic Itineraries (IEMADI), where multiple software agents are dispatched in parallel to perform tasks based on the query assigned to them. IEMADI decides the itinerary for an agent dynamically at each hop using local information. Through mathematical analysis and simulation, we compare the performance of IEMADI with a well known static itinerary based protocol with respect to energy consumption and response time. The results show that IEMADI provides better performance than the static itinerary based protocols.