• ETRI Journal
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• v.30 no.5
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• pp.696-706
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• 2008

With the increasing need for intelligent environment monitoring applications and the decreasing cost of manufacturing sensor devices, it is likely that a wide variety of sensor networks will be deployed in the near future. In this environment, the way to access heterogeneous sensor networks and the way to integrate various sensor data are very important. This paper proposes the common system for middleware of sensor networks (COSMOS), which provides integrated data processing over multiple heterogeneous sensor networks based on sensor network abstraction called the sensor network common interface. Specifically, this paper introduces the sensor network common interface which defines a standardized communication protocol and message formats used between the COSMOS and sensor networks.

• The KIPS Transactions:PartD
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• v.16D no.2
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• pp.177-184
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• 2009

Environmental monitoring systems are widely developed for analyzing environment and understanding an ecosystem according to the advance of wireless communication and various sensing techniques. To extract useful information, it requires high cost for processing a query, because these systems have to handle huge volume of raw sensor data which is transmitted from a wide area in environmental monitoring applications. Besides, it is also hard to answer an user defined query which requests to check current and near future condition. In this paper, we propose the monitoring system structure for processing a user defined query for environmental monitoring. It also describes the utilization of sensor data filtering and abstraction model. The designed abstraction model which is based on the slope grid in GIS supports fast data access and update. To analyze condition, the extracted data from abstraction model of each sensor type is combined in a query processor. It is useful to provide meaningful information to users.

• Journal of KIISE:Computing Practices and Letters
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• v.14 no.3
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• pp.281-285
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• 2008

Wireless sensor networks are closely related with the geometric environment in which they are deployed. We consider the probable case when a routing protocol runs on an environment with many complex obstacles like downtown surroundings. In addition, there are no unrealistic assumptions in order to increase practicality of the protocol. Our goal is to find a routing protocol for maximizing network lifetime by using only connectivity information in the complex sensor network environment. We propose a topology-based routing algorithm that accomplishes good performance in terms of network lifetime and routing complexity as measures. Our routing algorithm makes routing decision based on a weighted graph as topological abstraction of the complex network. The graph conduces to lifetime enhancement by giving alternative paths, distributing the skewed burden. An energy estimation method is used so as to maintain routing information without any additional cost. We show how our approach can be used to maximize network lifetime and by extensive simulation we prove that out approach gives good results in terms of both measures-network lifetime and routing complexity.

• Journal of Korea Society of Industrial Information Systems
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• v.14 no.2
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• pp.72-80
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• 2009

In this parer, we propose a hardware abstraction architecture(HAA) for low cost flash memories that can be applicable to wireless sensor nodes. The proposed HAA consists of three layers. The three layers are 1) HHL(Hardware Interlace Layer), HAL(Hardware Adaption Layer), and HPL(Hardware Presentation Layer), where HIL provides a platform independent interlace to applications of upper layers, HAL performs hardware resource management, program status control, and generation of logical instructions as main core of the HAA, and HPL initializes hardware and communicates data between MCU and flash memory. We implemented our HAA on AT45DB flash memory, and the HAA used 4,384 bytes program memory and 195 bytes data memory respectively. Since the proposed HAA is composed of well defined three layers and shows a low utilization of memory, it can provides a high efficiency in terms of flexibility, scalability, and re-usability, and thus the HAA is well suited for wireless sensor nodes.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.11
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• pp.2569-2574
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• 2010

In this paper, we introduce an efficient energy management using a notion of virtual energy system for shared solar-powered sensor network. Virtual energy system is an abstraction that allows sensor network applications on a node to reserve their own fractions of the shared solar cell and the shared rechargeable battery, hence achieving logically partition of a shared renewable power source. Our results show that our design and implementation are reliable, lightweight and efficient, allowing proper isolation of energy consumption among applications.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.9
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• pp.2127-2133
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• 2010

In this paper, we proposed an architecture for supporting sensor transparency in sensor node operating systems, design the standard APIs (Application Programming Interfaces) and sensor device abstraction to provide the sensor transparency and implemented the sensor transparency in the TinyOS, the most well known sensor node operating system. With the proposed sensor node operating system which can support the sensor transparency, application developers can develop the target applications independent to each sensor device by using the standard APIs provided by the sensor node operating system and the sensor device manufacturers also can develop sensor device drivers by using the standard hardware interfaces and HAL (Hardware Adaptation Layer) interfaces independent to the specific hardware platform of sensor nodes.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2008.04a
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• pp.85-86
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• 2008

다수 이기종 센서 네트워크로부터 수집한 대량의 센싱 데이터를 통합 처리/저장/관리/검색하고, 이로부터 실시간 이벤트정보 및 적합한 서비스를 제공하며, 다수 이기종 센서 네트워크 기반 USN 서비스의 효율적 개발을 지원하는 USN 미들웨어 플랫폼에 대한 개념모델 및 아키텍쳐, 기능 및 표준화 동향을 설명한다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.1B
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• pp.53-61
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• 2010

M2M Platform is the future ubiquitous network technologies which provide the integrated service with the networks and devices. It requires the standardized message protocols among the sensor applications. In this study, we developed the message protocols that support the data abstraction and interoperability among application systems with characteristics of sensor systems. The message protocols consist of the data representation formats and data exchange functions.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2010.10a
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• pp.531-534
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• 2010

In this paper, we introduce an efficient energy management using a notion of virtual energy system for shared solar-powered sensor network. Virtual energy system is an abstraction that allows sensor network applications on a node to reserve their own fractions of the shared solar cell and the shared rechargeable battery, hence achieving logically partition of a shared renewable power source with no change in design and implementation. Our results show that our design and implementation are reliable, lightweight and efficient, allowing proper isolation of energy consumption among applications.

• The Journal of the Korea Contents Association
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• v.7 no.2
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• pp.51-62
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• 2007

Recently microcontrollers are being used in sensor networks to handle sophisticated control and monitoring activities. As applications become more sophisticated, their design and development processes become more complex which consequently necessitates the use of an operating system to manage the complexity and provide an abstraction for portability of code. This paper presents a Low-power real-time operating system, called UbiFOS-USN, designed for sensor networks. We present some of the features that make UbiFOS-USN appropriate especially for small, low-cost microcontrollers typically found in sensor networks. Through experimental results, we show that UbiFOS-USN is quite efficient for a sensor network, both in terms of system performance and memory requirement.