• IEMEK Journal of Embedded Systems and Applications
• /
• v.11 no.2
• /
• pp.79-86
• /
• 2016

In wireless sensor networks, increasing the sensing rate of each node to improve the data accuracy usually incurs a decrease of network lifetime. In this study, an energy-adaptive data compression scheme is proposed to efficiently control the sensing rate in an energy-harvesting wireless sensor network (WSN). In the proposed scheme, by utilizing the surplus energy effectively for the data compression, each node can increase the sensing rate without any rise of blackout time. Simulation result verifies that the proposed scheme gathers more amount of sensory data per unit time with lower number of blackout nodes than the other compression schemes for WSN.

• Proceedings of the KSRS Conference
• /
• 2003.11a
• /
• pp.790-792
• /
• 2003

The remote sensing image server provides advanced image serving capabilities for geospatial image. Wide seamless image mosaics of Landsat 5 over GMS countries, which exceed a 15 GB or more in size per image, can integrate with other GIS map servers. The approach of two improvement algorithms leads to speed up the response time while preserving the data quality. This system does not only provide images on the web, but also provide GIS layers to WMS client map servers. The advantage of this approach is its efficiency lower cost in terms of cost, time and updating to obtain and utilize remote sensing image.

• Proceedings of the KSRS Conference
• /
• 2003.11a
• /
• pp.1389-1389
• /
• 2003

• Proceedings of the IEEK Conference
• /
• 1998.06a
• /
• pp.526-529
• /
• 1998

This paper describes new sense amplifier with fast sensing delay time of 0.54ns and 32kb CMOS embedded SRAM with 4.67ns access time for a 3-V powr supply. It was achieved using the sense amplifier with multiple point sensing scheme and high speed bit-line scheme. The sense amplifier saves 25% of the power dissipation compared with the conventional one while maintaining a very short sensing delay. The SRAM uses 0.5.mu.m double-polysilicon and triplemetal CMOS process technology. A die size is 1.78mm*2.13mm.

• Journal of Electrical Engineering and information Science
• /
• v.3 no.3
• /
• pp.300-305
• /
• 1998

This paper describes new sense amplifier with fast sensing delay time of 0.54ns and 32kb CMOS embedded SRAM with 4.67 ns access time for a 3-V power supply. It was achieved using the sense amplifier with multiple point sensing scheme and highs peed bit-line scheme. The sense amplifier saves 25% of the power dissipation compared with the conventional one while maintaining a very short sensing delay. The SRAM uses 0.5m double-polysilicon and triple-metal CMOS process technology. A die size is 1.78${\times}$mm2.13mm.

• Bulletin of the Korean Mathematical Society
• /
• v.61 no.2
• /
• pp.479-488
• /
• 2024

Convergence to a steady state in the long term limit is established for global weak solutions to a chemotaxis model with degenerate local sensing and consumption, when the motility function is C¹-smooth on [0, ∞), vanishes at zero, and is positive on (0, ∞). A condition excluding that the large time limit is spatially homogeneous is also provided. These results extend previous ones derived for motility functions vanishing algebraically at zero and rely on a completely different approach.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.10 no.4
• /
• pp.1555-1570
• /
• 2016

For monitoring forest fires, a real-time system to prevent fires in wider areas should be supported consistently. However, there has still been a lack of the support for real-time system related to forest fire monitoring. In addition, the 'real-time' processing in a forest fire detection system can lead to excessive consumption of energy. To solve these problems, the intelligent data acquisition of sensing nodes is required, and the maximum energy savings as well as rapid and accurate detection by flame sensors need to be done. In this regard, this paper proposes a node built-in filter algorithm for intelligent data collection of sensing nodes for the rapid detection of forest fires with focus on reducing the power consumption of the remote sensing nodes and providing efficient wireless sensor network-based forest environment monitoring in terms of data transmission, network stability and data acquisition. The experimental result showed that battery life can be extended through the intelligent sampling of remote sensing nodes, and the average accuracy of the measurement of flame detection based on the distance is 44%.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.36 no.6C
• /
• pp.376-383
• /
• 2011

Since the first arrival path may not be the strongest path of UWB(Ultra Wide Band) multipath channels, this makes ToA(Time-of-Arrival) estimation becomes a challengeable issue. Furthermore, because of ultra bandwidth of received signals, the compressed sensing theory is employed to reduce the complexity caused by very high Nyquist sampling rate in coherent UWB receivers. In this paper, we propose a ToA estimation scheme which provides precise estimation performance, while exploiting the benefits of compressed sensing-based UWB receivers. Simulation results show that the proposed scheme can outperform other low complexity schemes in a wide range of signal-to-noise ratios.

• Korean Journal of Remote Sensing
• /
• v.24 no.1
• /
• pp.79-89
• /
• 2008

Irregular temporal sampling is a common feature of geophysical and biological time series in remote sensing. This study proposes an on-line system for reconstructing observation image series contaminated by noises resulted from mechanical problems or sensing environmental condition. There is also a high likelihood that during the data acquisition periods the target site corresponding to any given pixel may be covered by fog or cloud, thereby resulting in bad or missing observation. The surface parameters associated with the land are usually dependent on the climate, and many physical processes that are displayed in the image sensed from the land then exhibit temporal variation with seasonal periodicity. A feedback system proposed in this study reconstructs a sequence of images remotely sensed from the land surface having the physical processes with seasonal periodicity. The harmonic model is used to track seasonal variation through time, and a Gibbs random field (GRF) is used to represent the spatial dependency of digital image processes. The experimental results of this simulation study show the potentiality of the proposed system to reconstruct the image series observed by imperfect sensing technology from the environment which are frequently influenced by bad weather. This study provides fundamental information on the elements of the proposed system for right usage in application.

• Proceedings of the KSRS Conference
• /
• 2002.10a
• /
• pp.448-453
• /
• 2002

Remote sensing technology is one of the most powerful tools for human to know the nature and their living environment. However, before microwave remote sensing was developed and applied, remote sensing application was limited strongly by weather and time. Microwave remote sensing technology solves the problem. It makes us to have the capability to acquire information at all time of the day and under all weather condition, and make remote sensing technology be used in more wider area. Microwave remote sensing system include mainly Synthetic Aperture Radar (SAR), Microwave Radiometer, Microwave Scatterometer, and Altimeter (ALT). As SAR can acquire image whose spatial resolution is similar with visible and infrared image, it is paying much attention to and playing a more and more important role in earth observation. In recent year, the development of new SAR technology (multi-band and multi-polarization technology, InSAR technology, D-InSAR technology, and so on) makes SAR remote sensing go to an new stage, and its application area become more and more widely. The first Synthetic Aperture Radar (SAR) in the world appeared in 1960. After that, SAR and its application all developed very fast. Some radar satellites launched and run (include Seasat-A in 1978, ERS-1 in 1991, JERS-1 in 1992, Radarsat in 1995, and so on) promote SAR research and application in world greatly. China began to develop its SAR sensor and research SAR application in 1970s. After more than 30 years' research, it get some important development in sensor development data processing method, and application. Some operational systems have been used and play an important role. This paper will introduce the development of SAR technology and its application in China.