• Journal of KIISE:Computer Systems and Theory
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• v.34 no.11
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• pp.572-580
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• 2007

Wireless sensor networks are sensing, computing and communication infrastructures that allow us to monitor, instrument, observe, and respond to phenomena in the harsh environment. Generally, the wireless sensor networks are composed of many deployed sensor nodes that were designed to be very cost-efficient in terms of production cost. For example, UC Berkeley's MICA motes have only 8-bit CPU, 4KB RAM, and 128KB FLASH memory space. Therefore, sensor operating systems that run on the sensor nodes should be able to operate efficiently in terms of the resource management. In this paper, we present a dynamic threads stack management scheme for space-constrained and multi-threaded sensor operating systems. In this scheme, the necessary stack space of each function is measured on compile-time. Then, the information is used to dynamically allocate and release each function's stack space on run-time. It was implemented in Nano-Qplus sensor operating system. Our experimental results show that the proposed scheme outperforms the existing fixed-size stack allocation mechanism.

• Proceedings of the Korean Information Science Society Conference
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• 2001.04a
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• pp.487-489
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• 2001

인터넷과 무선 이동통신 등이 보편화되면서 두 기술을 접목한 WAP(Wireless Application Protocol)[1]이 등장하였으며, 다수의 사용자 요구를 동시에 효율적으로 처리하면서 다양한 문서 단말기로부터 요청을 신속하게 처리할 수 있는 WAP 게이트웨이(gateway)에 대한 연구가 여러 연구 그룹에서 수행되고 있다. WAP 스택은 이러한 연구 중의 가장 기본적인 기술이다. 본 논문에서는 Java의 기본적인 서비스인 멀티쓰레드를 이용하고, 컨테이너 유효 리소스의 효율적 관리를 위해 접속 풀링(connection pooling) 기능을 적용하여 UDP(User Datagram Protocol)[4], WTP(Wireless Transaction Protocol)[2], WSP(Wireless Session Protocol)[3] 계층을 설계한다. 설계 방법론은 UML(Unified Modeling Language)을 사용한다.

• Journal of KIISE:Information Networking
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• v.30 no.2
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• pp.244-251
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• 2003

As the Internet and wireless mobile communication is being widespread, the WAP (Wireless Application Protocol) that merges these two technologies has emerged. Also, the research of the WAP gateway that enables efficient processing of multiple user demands concurrently and prompt response to requests from various wireless devices has been performed in many working groups. The WAP stack is the most fundamental technology among these researches. In this paper, we implement the WAP container utilizing the JAVA's multithreading and applying to the connection pooling technique to manage the available resource in the container efficiently. Also, we design and implement the WTP(Wireless Transaction Protocol) layer and the UDP(User Datagram Protocol) layer based on the priority Policy. Our design and implementation showed the shorter waiting time than that of the existing FCFS(First-Come, First-Served) system in the transaction layer and its efficiency was proved through simulation.