• International Journal of Computer Science & Network Security
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• v.21 no.4
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• pp.255-263
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• 2021

Smart grid is a fully-automated, bi-directional, power transmission network based on the physical grid system, which combines sensor measurement, computer, information communication, and automatic control technology. Blockchain technology, with its security features, can be integrated with Smart Grids to provide secure and efficient power management and transmission. This paper dicusses the deployment of Blockchain technology in Smart Grid. It presents application areas and protocols in which blockchain can be applied to in securing smart grid. One application of each area is explored in detail, such as efficient peer-to-peer transaction, lower platform costs, faster processes, greater flexibility in power generation to transmission, distribution and power consumption in different energy storage systems, current barriers obstructing the implementation of blockchain applications with some level of maturity in financial services but concepts only in energy and other sectors. Wide range of energy applications suggesting a suitable blockchain architecture in smart grid operations, a sample block structure and the potential blockchain technicalities employed in it. Also, added with efficient data aggregation schemes based on the blockchain technology to overcome the challenges related to privacy and security in the smart grid. Later on, consensus algorithms and protocols are discussed. Monitoring of the usage and statistics of energy distribution systems that can also be used to remotely control energy flow to a particular area. Further, the discussion on the blockchain-based frameworks that helps in the diagnosis and maintenance of smart grid equipment. We have also discussed several commercial implementations of blockchain in the smart grid. Finally, various challenges have been discussed for integrating these technologies. Overall, it can be said at the present point in time that blockchain technology certainly shows a lot of potentials from a customer perspective too and should be further developed by market participants. The approaches seen thus far may have a disruptive effect in the future and might require additional regulatory intervention in an already tightly regulated energy market. If blockchains are to deliver benefits for consumers (whether as consumers or prosumers of energy), a strong focus on consumer issues will be needed.

• ETRI Journal
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• v.18 no.1
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• pp.1-14
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• 1996

We have experimentally observed and theoretically analyzed the gain dependent optimum repetition rates of a hybrid-type active and passive mode locked laser pulses in an erbium-doped fiber laser of the figure-of-eight geometry by utilizing a nonlinear amplifier loop mirror (NALM) as a saturable absorber and a directional-coupler type electro-optic modulator as an active mode locker. Transform-limited mode-locked pulses of about 10 ps width were obtained at repetition rates which correspond to harmonics of the cavity fundamental frequency and depend on the optical amplifier gain in the NALM.

• ETRI Journal
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• v.29 no.2
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• pp.162-168
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• 2007

A new scheme for bi-directional HDTV/Gigabit Ethernet/CATV transmission over a hybrid dense-wavelength-division-multiplexing passive optical network (DWDM-PON) is proposed and demonstrated. It is based on injection-locked vertical-cavity surface-emitting lasers and distributed-feedback laser diodes as transmitters. Services with 129 HDTV channels, a 1.25 Gbps Gigabit Ethernet connection, and 77 CATV channels are successfully demonstrated over 40 km single-mode fiber links. Good performance of bit error rate, carrier-to-noise ratio, composite second order, and composite triple beat is achieved in our proposed bidirectional DWDM-PON.

• The Journal of the Acoustical Society of Korea
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• v.15 no.2E
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• pp.45-49
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• 1996

From the reverberation signals received in the shallower water, the surface scattered signals are identified by using the multipath eigneray model that provides launch angles, grazing angles and transmission loss from the high frequency directional source to and from the rough surface. For small scale surface waves, the perturbation method is used to compute the backscattering strength for various grazing angles and wind speeds. A scheme to inversely estimate the wind speed, by which the observed surface reverberation levels are produced, has been tested. In result, for low grazing angles the perturbation method can be used to predict the backscattering stregth, thereby the surface wind can be indirectly estimated.

• Advanced Composite Materials
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• v.18 no.4
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• pp.365-379
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• 2009

Epoxy/S2-glass reinforced composites (SGRPs) infused with Cloisite 30B nanoclays were manufactured using the vacuum assisted resin infusion molding (VARIM) process. Prior to infusion, the matrix and clays were thoroughly mixed using a direct mixing technique (DMT) and a high shear mixing technique (HSMT) to ensure uniform dispersion of the nanoclays. Structures with varying clay contents (1-3 wt%) were manufactured. Both pristine and SGRP nanocomposites were then subjected to mechanical testing. For the specimens manufactured by DMT, the tensile, flexural, and compressive modulus increased with increasing the clay content. Similarly, the tensile, flexural, compressive, interlaminate shear and impact strength increased with the addition of 1 wt% clay: however the trend reversed with further increase in the clay content. Specimens manufactured by HSMT showed superior properties compared to those of nanocomposites containing 1 wt% clay produced by DMT. In order to understand these phenomena a morphological study was conducted. Transmission electron microscopy (TEM) micrographs revealed that HSMT led to better dispersion and changed the nanoclay structure from orderly intercalation to disorderly intercalation giving multi-directional strength.

• Journal of KSNVE
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• v.7 no.4
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• pp.621-629
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• 1997

For computer aided design and costruction of low noisy power plants, indoor and outdoor noise prediction program has been developed. The program utilizes the predefined data of noise sources and building materials and has the faculty to estimate the source level using the empirical formula in case of the measured data not being available. In the noise prediction, the mutual noise propagation between indoor and outdoor sites are considered. The outdoor noise source in the calculation of geometric divergence effects is modelled as the omni-directional finite line or planar source according to the source geometry and the receiving points. Outdoor noise prediction is carried out to consider the diffraction effect due to plant structures as well as the attenuation effect due to atmospheric absorption and soft ground. The results of indoor and outdoor noise prediction for a recently constructed diesel engine power plant show good agreement with the measured.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.15 no.6 s.99
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• pp.738-748
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• 2005

The ship radiated noise level fluctuates by the difference of interference and reverberation according to measurement methods and environmental conditions. These phenomena cause error of the source level estimation even in the same environment conditions. This paper describes a quantitative analysis and a reduction method for an error value to the source level estimation in spatial and temporal interference environment. The design criteria of the radiated noise measurement array composed of omni-directional hydrophones and the source level accuracy in the deep water range are given. The source level accuracy in the shallow water range is also derived based on the statistical model of the multiple reflection paths. The results are verified using the water tank experiment and the sea trial.

• Proceedings of the KIEE Conference
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• 2005.07a
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• pp.456-458
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• 2005

송전선로에서 발생하는 고장은 낙뢰나 수목접지로 인한 순간 고장이 대다수를 차지한다. 따라서 송전선로 보호 기능에 있어서 재폐로 기능은 계통의 안정성 향상과 공급 신뢰도의 제고를 위해서 중요한 역할을 담당한다. 본 논문에서는 154kV 송전선로 보호에 널리 사용되고 있는 디지털 방향비교 보호방식(Directional Comparison Blocking Scheme)에서 보호 구간 내부에 고장이 진전되어 발생했을 때, 재폐로 기능의 동작 특성에 대한 성능 검증 방안에 대해서 기술한다.

• Proceedings of the IEEK Conference
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• 2003.07a
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• pp.322-325
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• 2003

In this paper, path loss characteristics in a curved subway tunnel are measured and analyzed. The measurement is carried out in the frequency bands of 2.45GHz and 5.8GHz. A directional antenna is employed for transmission and an omnidirectional antenna for reception. This measurement is performed in the subway tunnel in the vicinity of the Daejon station. The tunnel is curved and its cross section is arch-shaped. The path loss is measured with the location of the transmitter antenna fixed and the receiver antenna moving in the tunnel. The measured path loss ratio is about 0.1dBm/m. Also, the signal received from the antenna located on the outer side of curve in the tunnel experiences weaker path loss.

• Proceedings of the IEEK Conference
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• 2000.06e
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• pp.113-116
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• 2000

In this paper presents the portable wireless ECG data detection and diagnosis system based on discreet wavelet transform. An algorithm based on wavelet transform suitable for real time implementation has been developed in order to detect ECG characteristics. In particular, QRS complex, S and T waves may be distinguished form noise, baseline drift or artifacts. Proposed telemetry system that a transmitting media using radio frequency(RF) for the middle range measurement of the physiological signals and receiving media using optical for electromagnetic interference problem. A standard hi-directional serial communication interface between the telemetry system and a personal computer or laptop, allows read-time controlling, diagnosing and monitoring of system. A portable telemetry system within a size. of 65${\times}$125${\times}$45mm consists of three parts: a digital signal processing part for physiological signal detect or diagnose, RF transmitter for data transfer and a optical receiver for command receive. Advantages of proposed telemetry system is wireless middle range(50m) FM transmission, reduce electromagnetic interference to a minimum. which enables a comfortable diagnosis system at home.