• KSII Transactions on Internet and Information Systems (TIIS)
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• v.6 no.2
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• pp.468-479
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• 2012

Recent advances in wireless communications and electronics has enabled the development of machine-to-machine (M2M) communications. This communication paradigm has been expected as an automated control and report solution for smart grid. The smart grid enables customers and operators to utilize the collected usage information from a large number of meters with transceivers for efficiency and safety. In this paper, we introduce architecture, requirements and challenges of M2M communications for smart grid. We extract technical issues that should be resolved in M2M communications to support the smart grid via third-generation partnership project (3GPP) cellular networks. We then present the current state of the art of research results to deal with such issues. Finally, we outline the open research issues.

• International Journal of Naval Architecture and Ocean Engineering
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• v.3 no.2
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• pp.141-149
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• 2011

The world is facing a challenge in meeting its needs for energy. Global energy consumption in the last halfcentury has increased very rapidly and is expected to continue to grow over the next 50 years. However, it is expected to see significant differences between the last 50 years and the next. This paper aims at introducing a good solution to replace or work with conventional marine power plants. This includes the use of fuel cell power plant operated with hydrogen produced through water electrolysis or hydrogen produced from natural gas, gasoline, or diesel fuels through steam reforming processes to mitigate air pollution from ships.

• Earthquakes and Structures
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• v.3 no.5
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• pp.675-694
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• 2012

The 2008 Iwate-Miyagi Nairiku earthquake ($M_w$ 6.9, $M_{jma}$ 7.2) occurred on 14 June 2008 in Japan. The amplification and asymmetric waveform of the vertical acceleration at the ground surface recorded by accelerometers at station IWTH25, situated 3 km from the source, were remarkable in two ways. First, the vertical acceleration was extremely large (PGA = 38.66 $m/s^2$ for the vertical component, PGA = 42.78 $m/s^2$ for the sum of the three components). Second, an unusual asymmetric waveform, which is too far above the zero acceleration axis, as well as large upward spikes were observed. Using a multidegree-of-freedom (MDF) system consisting of a one-dimensional continuum subjected to vertical acceleration recorded at a depth of 260 m below ground level, the present paper clarifies numerically that these singular phenomena in the surface vertical acceleration records occurred as a result of the jumping and collision of a layer in vertical motion. We herein propose a new mechanism for such jumping and collision of ground layers. The unexpected extensive landslides that occurred in the area around the epicenter are believed to have been produced by such jumping under the influence of vertical acceleration.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.25 no.3
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• pp.289-295
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• 2014

In this paper a wideband active balun using advanced phase correction architecture is proposed. The proposed active balun is constructed with each different architecture of active balun combined with the cascode architecture to improve phase correction performance compared with conventional phase correction techniques. Operating over 0.6~2.0 GHz band, the proposed balun shows $10^{\circ}$ of phase error and 2 dB of gain error with 7 mW power consumption from 1.8 V supply voltage.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.4A
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• pp.439-446
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• 2004

This paper describes high speed and low power design techniques for an 8-bit 500MSamples/s CMOS 2-step ADC. Instead of the conventional closed-loop architecture, the newly proposed ADC adopts open-loop architecture and uses a reset-switch to reduce loading time in an environment of big parasitic-capacitances of mux-array. An analog-latch is also used to reduce power consumption. Simulation result shows that the ADC has the SNDR of 46.91㏈ with a input frequency of 103MHz at 500Msample/s and consumes 203㎽ with a 1.8V single power supply. The chip is designed with a 0.18mm 1-poly 6-metal CMOS technology and occupies active area of 760${\mu}{\textrm}{m}$*800${\mu}{\textrm}{m}$.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• v.6 no.2
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• pp.75-84
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• 2002

Using good properties of an optimal normal basis of type I in a finite field ${\mathbb{F}}_{2^m}$, we present a design of a bit serial multiplier of Berlekamp type, which is very effective in computing $xy^2$. It is shown that our multiplier does not need a basis conversion process and a squaring operation is a simple permutation in our basis. Therefore our multiplier provides a fast and an efficient hardware architecture for a bit serial multiplication of two elements in ${\mathbb{F}}_{2^m}$.

• Journal of Digital Convergence
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• v.12 no.12
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• pp.351-356
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• 2014

Generally, although securing the condition and location of container freights or normal freights, which load a fresh goods, has been a very important issue in the cold-chain system implementations, it has not gotten out of the traditional methods in the related business world yet. To solve this problem, we propose the designing method and architecture which can be used to implement a smart cold-chain monitoring automation systems. The proposed system architecture is based on the oneM2M standards, and it has 3 layers and entities, which can be implemented to S/W and H/W, network services layer and entity, common services layer and entity, application layer and entity. Based on this architecture, we will not only expect an innovative retrenchment of distribution cost, but also automatically secure the freight condition and location.

• Journal of the Korean Institute of Landscape Architecture
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• v.32 no.6 s.107
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• pp.95-102
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• 2005

This study was carried out to find out the heavy metal contents and the physico-chemical properties for the improvement of dredged soils which widely exist in lowlands of Korea. At first all the average heavy metal contents were close to background level and were much lower than concern level of the Soil Environment Conservation Act of Korea. And the results of physical analyses of soils showed on the average $2.46\~2.74 Mg/m^3$ in Particle density, $0.45\~2.45 kg/kg$ in soil water contents, $0.34\~0.90 Mg/m^3$ in bulk density, $0.67\~0.87m^3/m^3$ in porosity, $2.18\times10^{-5}\~1.20\times10^{-8} m/s$ in saturated hydraulic conductivity, R0.12\~0.65 m^3/m^3$ in available water contents. Finally the results of chemical analyses of soils showed on the average $6.5\~8.2\;in\; pH,\;5\~48 g/kg\;in\; OM,\;0.48\~4.51g/kg\;in\;T-N,\;19\~25mg/kg$ in available phosphate, $0.28\~11.80 dS/m\;in\;EC,\;8.7\~38.1cmol/kg$ in CEC, respectively Accordingly, the physicochemical properties of soils ought to be analyzed accurately before dredging for effective using of dredged soils. And it will be more effective, if the dredged soils are used with proper balance among each content of components with consideration to the physicochemical properties of common soils.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.27 no.9
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• pp.449-454
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• 2015

In this study, the effects of lock operations on the infiltration rates for the two window types sliding and lift sliding (LS) are investigated through experiment and simulation. The airtightness levels of the two window types-with locks both on and off-were measured according to the KS F 2292 Test method of airtightness that is used for windows and doors. The air-flow rates of both window types with the locks on for a pressure differential of 10 Pa are $1.98m^3/(m^2h)$ and $1.68m^3/(m^2h)$, respectively; with the locks off, the air-flow rates of the sliding and LS windows are $2.64m^3/(m^2h)$ and $5.83m^3/(m^2h)$, respectively, whereby the air-flow rates are 33% higher for sliding and 247% higher for LS. The air change per hour (ACH) was calculated using the ventilation-simulation software CONTAM. For the sliding window, the ACH changed from 0.45 to 0.57 when the lock was operated from on to off, representing an increase of 27%. For the LS window, the ACH changed from 0.29 to 0.81, showing an increase of 179%.

• Journal of Navigation and Port Research
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• v.36 no.3
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• pp.215-223
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• 2012

To examine the interaction of the floating pontoon with a steel moment resisting frame, the static structural analysis is carried out, in which the pressure load are calculated from the forgoing fluid dynamic analysis, varying the period of wave from 3 to 15 second and for 3 cases of depth of pontoon, 1.5, 2.0, 2.5m. As results, it has shown that RAO-pitch has the linear relationship with the increase of moment of the frame and the curvature of pontoon is reversely proportional to the stiffness of pontoon. By synthesizing these results, an estimation method is proposed, which predicts the moment of frame of the different depth of pontoon based on the analysis result of an arbitrary depth of a floating pontoon. The estimation result shows considerably good agreement, compared with the analysis result.