• Journal of Radiation Protection and Research
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• v.25 no.4
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• pp.197-205
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• 2000

A prototype electronic dosimeter(PED) adopting a silicon PIN diode detector as a radiation detector has been developed, manufactured and test-evaluated. A radiation signal processing circuit has been electronically tested and then the radiation detection characteristics of this PED has been performance-tested by using a reference photon radiation field. As a result in a electronic performance test, radiation signals from a detector were well observed in the signal processing circuit. The radiation detection sensitivity of this PED after several test-irradiations to $^{137}Cs$ gamma radiation source appeared to be 1.85 cps/$Gy{\cdot}h^{-1}$ with 19.3% of the coefficient of variation, which satisfied the performance criteria for the active personnel radiation monitor. Further improvement of the electronic circuit and operating program will enable the PED to be used in personal monitoring purpose.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.44 no.6 s.360
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• pp.24-30
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• 2007

In this paper, an energy detection-based low power, low complexity IR-UWB receiver in multipath impulse radio channel is presented. The proposed receiver has a simple 1-bit sampler for energy detection. Also, multipath signal received from multipath impulse radio channel is amplified and envelope of the signal is detected. Then, energy detection technique using integrator by summing multipath signals in certain period is adopted to minimize the BER loss by simple energy detection. In particular, in acquisition of a sample signal, SNR is additionally improved using a digital sampler. Symbol decision using several sampled signals is performed and thus the process of symbol synchronization is significantly simplified. Also, it is effectively designed to be compatible with influences of multipath and timing error. In addition, the proposed receiver complexity is reduced using pulse decision window. The performance of the proposed receiver is simulated based on IEEE 802.15.4a channel model and the algorithms are implemented on FPGA.

• Journal of Satellite, Information and Communications
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• v.12 no.2
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• pp.89-93
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• 2017

This paper introduces an energy harvesting system that generates energy by collecting multi-band RF signals using buck-boost DC-DC converter. In an environment where the resistance of load using the collected electric energy is constantly changing, a buck-boost DC-DC converter is used in which the input resistance of the DC-DC converter does not change even if the load resistance changes. Since the frequency band of the input RF signal varies, the rectifier is designed for each band so that multiple bands can be processed, and a matching circuit is added to each band in front of the rectifier. For a rectifier to collect very small RF signals, a circuit is designed so that a constant voltage is obtained according to a very small input signal by devising a method of continuously accumulating the voltages collected and generated in each band. It is confirmed that the output efficiency can reach up to 20% even for the RF signal having the input of -20 dBm.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.1999-2005
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• 2005

Collaboration in wireless sensor networks must be fault-tolerant due to the harsh environmental conditions in which such networks can be deployed. This paper focuses on finding signal processing algorithms for collaborative target detection based on the generalized approach to signal processing in the presence of noise that are efficient in terms of communication cost, precision, accuracy, and number of faulty sensors tolerable in the wireless sensor network. Two algorithms, namely, value fusion and decision fusion constructed according to the generalized approach to signal processing in the presence of noise, are identified first. When comparing their performance and communication overhead, decision fusion is found to become superior to value fusion as the ratio of faulty sensors to fault free sensors increases. The use of the generalized approach to signal processing in the presence of noise under designing value and decision fusion algorithms in wireless sensor networks allows us to obtain the same performance, but at low values of signal energy, as under the employment of universally adopted signal processing algorithms widely used in practice.

• Biotechnology and Bioprocess Engineering:BBE
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• v.7 no.1
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• pp.52-55
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• 2002

Flow cytometric techniques were used to investigate cell size, protein content and cell cycle behavior of recombinant Saccharomyces cerevisiae strains producing human lysozyme (HLZ). Two different signal sequences, the native yeast $MF\alpha1$ signal sequence and the rat $\alpha-amylase$ signal sequence, were used for secretion of HLZ. The strain containing the rat $\alpha-amylase$ signal sequence showed a higher level of internal lysozyme and lower specific growth rates. Flow cytometric analysis of the total protein content and cell size showed the strain harboring the native yeast signal sequence had a higher total protein content than the strain containing the rat $\alpha-amylase$ signal sequence. Cell cycle analysis indicated that the two lysozyme producing recombinant strains had an increased number of cells in the $G_2+M$ phase of the yeast cell cycle compared with the host strain SEY2102.

• Korean Journal of Materials Research
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• v.17 no.5
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• pp.239-243
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• 2007

The evaluation and comparison have been made for the EMI noise which was included in the signal from the sensors in the acoustic emission testing for the bottom plate of ground tank at full. The EMI signal has been classified into two types. One is the signal with very short AE count, and this signal possibly can be filtered by front end filter setting of the channel count with low level of 4 and high level of $10^8$. The other EMI signal occurred from CH 1, CH 3 and CH 10, and had high and constant duration with high energy and count (maximun duration > $10^5\;{\mu}s$), and has characteristic gradient of accumulation amplitude distribution. This signal should be removed in the AE signal evaluation by filtering, because this may affect to the total gradient.

• Geosystem Engineering
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• v.21 no.5
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• pp.251-261
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• 2018

With the urbanization in recent years, the power line interference noise in electromagnetic signal is increasing day by day, and has gradually become an unavoidable component of noises in magnetotelluric signal detection. Therefore, a kind of power line interference noise elimination method based on independent component analysis in wavelet domain for magnetotelluric signal is put forward in this paper. The method first uses wavelet decomposition to change single-channel signal into multi-channel signal, and then takes advantage of blind source separation principle of independent component analysis to eliminate power line interference noise. There is no need to choose the layer number of wavelet decomposition and the wavelet base of wavelet decomposition according to the observed signal. On the treatment effect, it is better than the previous power line interference removal method based on independent component analysis. Through the de-noising processing to actual magnetotelluric measuring data, it is shown that this method makes both the apparent resistivity curve near 50 Hz and the phase curve near 50 Hz become smoother and steadier than before processing, i.e., it effectively eliminates the power line interference noise.

• Journal of the Institute of Convergence Signal Processing
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• v.14 no.1
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• pp.45-50
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• 2013

Sensors have limited resources in sensor networks, so efficient use of energy is important. Representative clustering methods, LEACH, LEACHC, TEEN generally use direct transmission methods from cluster headers to a sink node to pass collected data. If clusters are located at a long distance from the sink node, the cluster headers exhaust a lot of energy in order to transfer the data. As a consequence, the life of sensors is shorten and re-clustering is needed. In the process of clustering, sensor nodes consume some energy and the energy depletion of the cluster headers meet another energy exhaustion. A method of transferring data from cluster headers to the sink using neighbor clusters is needed for saving energy. In this paper, we propose a novel routing method using a multi-hop transmission method in cluster sensor networks. This method uses the topology matrix which presents cluster topology. One-hop routing and two-hop routing are proposed in order to increase the energy efficiency.

• Proceedings of the Korean Geotechical Society Conference
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• 2001.03a
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• pp.469-476
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• 2001

The Ν-value in the standard penetration test(SPT) is affected by the magnitude of the rod penetration energy transmitted from the falling hammer as well as the geotechnical characteristics of the ground. Understanding of the striking energy efficiency in the SPT equipment is getting important for that reason. The energy efficiencies of the doughnut hammer with the hydraulic lift system and the automatic trip hammer system were investigated through field tests using the instrumented rod and wave-signal acquisition systems including the pile driving analyzer(PDA) . The rod energy ratio, ΕR$\_$r/ was defined as the ratio of the energy delivered to the drilling rod to the potential free-fall energy of the hammer. It appears that the type of the hammer and lift/drop system had a strong influence on the energy transfer mechanism and ΕR$\_$r/ also varies according to the energy instrumentation system and the analysis methods.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.7 no.3
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• pp.446-458
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• 2013

Recently, energy-efficient cellular transmission has received considerable research attention to improve the energy efficiency of wireless communication. In this paper, we consider a cellular network consisting of one base station (BS) and multiple user terminals and explore the network coding for enhancing the energy efficiency of cellular downlink transmission from BS to users. We propose the network coded cellular transmission scheme and conduct its energy consumption analysis with target outage probability and data rate requirements in Rayleigh fading environments. Then, the energy efficiency in Bits-per-Joule is further defined and analyzed to evaluate the number of bits delivered per Joule of energy cost. Numerical results show that the network coded cellular transmission significantly outperforms the traditional cellular transmission in terms of energy efficiency, implying that given a Joule of energy cost, the network coded cellular transmission scheme can deliver more bits than the traditional cellular transmission.