• Current Optics and Photonics
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• v.7 no.3
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• pp.237-247
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• 2023

In middle- and long-distance imaging systems, due to the atmospheric turbulence caused by temperature, wind speed, humidity, and so on, light waves propagating in the air are distorted, resulting in image-quality degradation such as geometric deformation and fuzziness. In remote sensing, astronomical observation, and traffic monitoring, image information loss due to degradation causes huge losses, so effective restoration of degraded images is very important. To restore images degraded by atmospheric turbulence, an image-restoration method based on improved compound multibranch feature fusion (CMFNetPro) was proposed. Based on the CMFNet network, an efficient channel-attention mechanism was used to replace the channel-attention mechanism to improve image quality and network efficiency. In the experiment, two-dimensional random distortion vector fields were used to construct two turbulent datasets with different degrees of distortion, based on the Google Landmarks Dataset v2 dataset. The experimental results showed that compared to the CMFNet, DeblurGAN-v2, and MIMO-UNet models, the proposed CMFNetPro network achieves better performance in both quality and training cost of turbulent-image restoration. In the mixed training, CMFNetPro was 1.2391 dB (weak turbulence), 0.8602 dB (strong turbulence) respectively higher in terms of peak signal-to-noise ratio and 0.0015 (weak turbulence), 0.0136 (strong turbulence) respectively higher in terms of structure similarity compared to CMFNet. CMFNetPro was 14.4 hours faster compared to the CMFNet. This provides a feasible scheme for turbulent-image restoration based on deep learning.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.17 no.8
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• pp.2140-2156
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• 2023

The Wireless Sensor Network (WSN), is constructed out of teeny-tiny sensor nodes that are very low-cost, have a low impact on the environment in terms of the amount of power they consume, and are able to successfully transmit data to the base station. The primary challenges that are presented by WSN are those that are posed by the distance between nodes, the amount of energy that is consumed, and the delay in time. The sensor node's source of power supply is a battery, and this particular battery is not capable of being recharged. In this scenario, the amount of energy that is consumed rises in direct proportion to the distance that separates the nodes. Here, we present a Hybrid Firefly Glow-Worm Swarm Optimization (HF-GSO) guided routing strategy for preserving WSNs' low power footprint. An efficient fitness function based on firefly optimization is used to select the Cluster Head (CH) in this procedure. It aids in minimising power consumption and the occurrence of dead sensor nodes. After a cluster head (CH) has been chosen, the Glow-Worm Swarm Optimization (GSO) algorithm is used to figure out the best path for sending data to the sink node. Power consumption, throughput, packet delivery ratio, and network lifetime are just some of the metrics measured and compared between the proposed method and methods that are conceptually similar to those already in use. Simulation results showed that the proposed method significantly reduced energy consumption compared to the state-of-the-art methods, while simultaneously increasing the number of functioning sensor nodes by 2.4%. Proposed method produces superior outcomes compared to alternative optimization-based methods.

• Journal of Biomedical Engineering Research
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• v.28 no.3
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• pp.429-440
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• 2007

A coded excitation has been studied to improve the performance for ultrasound imaging in term of SNR, imaging frame rate, contrast to tissue ratio, and so forth. However, it requires a complicated arbitrary waveform transmitter for each active channel that is typically composed of a multi-bit Digital-to-Analog Converter (DAC) and a linear power amplifier (LPA). Not only does the LPA increase the cost and size of a transmitter block, but it consumes much power, increasing the system complexity further and causing a heating-up problem. This paper proposes an optimized 1.5bit fourth order sigma-delta modulation technique applicable to design an efficient arbitrary waveform generator with greatly reduced power dissipation and hardware. The proposed SDM can provide a required SQNR with a low over-sampling ratio of 4. To this end, the loop coefficients are optimized to minimize the quantization noise power in signal band while maintaining system stability. In addition, the decision level for the 1.5 bit quantizer is optimized for a given input waveform, which results in the SQNR improvement of more than 5dB. Computer simulation results show that the SQNR of a FM(frequency modulated) signal generated by using the proposed method is about 26dB, and the peak side-lobe level (PSL) of its compressed waveform on receive is -48dB.

• Journal of Environmental Health Sciences
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• v.24 no.1
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• pp.54-61
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• 1998

This study was conducted in order to evaluate the treatment efficiencies of anaerobic packed and fluidized-bed biofilm and to investigate applicability in treating livestock wastewater. Biocarbonate alkalinity(BA) and volatile fatty acid(VFA) were about 3,230-3,270 mg/l, 3,790-3,126 mg/l(as CaCO$_3$) and 224-402 mg/l, 141-387 mg/l(as CH$_3$COOH), and VFA/BA ratio was about 0.069~0.12, 0.045-0.12 in packed and fluidized-bed biofilm. When COD loading rate was 6.0 kg COD/$m^3\cdot$ day in packed and fluidized-bed biofilm, methane gas production were 3.23 l/day and 4.38 l/day, respectively. In the same COD loading rate, methane gas production volumes per kg COD removal were 0.25 m$^3$ CH$_4$/kg COD$_{rm}$ and $0.28 m^3 CH_4/kg COD^{rm}$, respectively. At this time, it could be estimated that fluidized-bed biofilm was more high. In case of HRT 0.94 day(6.0 kg COD/$m^3\cdot$ day) and 11 day(0.5 kg COD/$m^3\cdot$ day), packed-bed biofilm showed 59% and 81% COD removal efficiency, respectively. While fluidized-bed biofilm showed 72% and 85% removal efficiency, respectively. It was showed that fluidized-bed biofilm was more efficient. Packed-bed biofilm was higher than fluidized in treatment efficiencies of organic matters, but required continuous treatment using combined system, because it was very exceeded over an environmental standard solidified from '96 year. In operating fluidized-bed biofilm, if farm house consider high power cost according to high circulation ratio in an economic point of view, it would have an effect that farm house use packed-bed biofilm as combined system in treating livestock wastewater.

• Journal of the Korean Institute of Gas
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• v.13 no.3
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• pp.15-21
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• 2009

Gas hydrate is an ice-like crystalline compound that forms at low temperature and high pressure conditions. It consists of gas molecules surrounded by cages of water molecules. Although hydrate formation was initially found to pose serious flow-assurance problems in the gas pipelines or facilities, gas hydrates have much potential for application in a wide variety of areas, such as natural gas storage and transportation. Its very high gas-to-solid ratio and remarkably stable characteristics makes it an attractive candidate for such use. However, it needs to be researched further since it has a slow and complex formation process and a high production cost. In this study, formation experiments have been carried out to investigate the effects of pressure, temperature, water-to-storage volume ratio, SDS concentration, heat transfer and stirring. The results are presented to clarify the relationship between the formation process and each factor, which consequently will help find the most efficient production method.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.21 no.6
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• pp.1490-1500
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• 1996

One of the important issues for multimedia communications over ATM netowrks is efficient use of net-work resources since transmitting video at low cost requires high utilization of channel bandwidth. In this paper, we propose an effective bandwidth estimation scheme for MPEG sources in ATM networks. It has been known difficult to allocate effective transmission bandwidth to MPEG sources due to its bursty charactersitics. The MPEG traffic stream can bemodeled using five traffic parameters:service rate, burst load ratio, interburst load ratio, burst period, and interburst period. Using these parameters, a transmission bandwidth for each source can be estimated, and the estimated bandwidth is applied synchronously to reduce the queue size in a buffer. For a simple network modelof a high speed link that multiplexes a number of virtual-circuit connections, simulations on adaptive bandwidth allocation were performed, and the results show that the queueing delay is significantly reduced, when compared to a fixed bandwidth allocation.

• International Journal of Highway Engineering
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• v.18 no.2
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• pp.61-71
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• 2016

PURPOSES: The objective of this study was to determine the optimum ratio of mix design, for a reclaimed asphalt pavement (RAP) content of 100%, for spray injection application. METHODS: A literature review revealed that spray injection is an efficient and cost-effective application for fixing small defective regions of an asphalt pavement. Rapid-setting polymer-modified asphalt mixtures prepared from two types of rapid-setting polymer asphalt emulsion were subjected to Marshall stability and wet track abrasion tests, in order to identify the optimum mix designs. RESULTS and CONCLUSIONS : Different mix designs of type A and type B emulsions were prepared using RAP and virgin aggregates, in order to compare the performance and determine the optimum mix design. The performance of mixtures prepared with RAP was superior to that of mixtures containing virgin aggregates. Moreover, for optimum ratio of the design, the binder content prepared from RAP was set to 1~2% lower than that consisting of virgin aggregates. Compared to their Type A counterparts, type B mixtures consisting of a reactive emulsion performed better in the Marshall stability and wet track abrasion tests. The initial results confirmed the advantages associated with using RAP for spray injection applications. Further studies will be performed to verify the difference in the optimum mix design and performance obtained in the lab-scale test and tests conducted at the job site by using the spray injection machine.

• Journal of Korea Multimedia Society
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• v.5 no.4
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• pp.458-467
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• 2002

There has been proposed many simplification algorithms for effectively decreasing large-volumed polygonal surface data. These algorithms apply their own cost function for collapse to one of fundamental simplification unit, such as vertex, edge and triangle, and minimize the simplification error occurred in each simplification steps. Most of cost functions adopted in existing works use the error estimation method based on distance optimization. Unfortunately, it is hard to define the local characteristics of surface data using distance factor alone, which is basically scalar component. Therefore, the algorithms cannot preserve the characteristic features in surface areas with high curvature and, consequently, loss the detailed shape of original mesh in high simplification ratio. In this paper, we consider the vector component, such as surface orientation, as one of factors for cost function. The surface orientation is independent upon scalar component, distance value. This means that we can reconsider whether or not to preserve them as the amount of vector component, although they are elements with low scalar values. In addition, we develop a simplification algorithm based on half-edge collapse manner, which use the proposed cost function as the criterion for removing elements. In half-edge collapse, using one of endpoints in the edge represents a new vertex after collapse operation. The approach is memory efficient and effectively applicable to the rendering system requiring real-time transmission of large-volumed surface data.

• Korean Journal of Construction Engineering and Management
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• v.20 no.2
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• pp.105-112
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• 2019

As the Construction Technology Promotion Act was revised in 2015, the term of Supervision was removed and Construction Management was included instead. The consideration of Construction Management shall be based on the cost plus fee method specified in the Criteria for the Cost of Construction Technology Services of the Ministry of Land, Infrastructure and Transport. Nevertheless, it is based on the construction cost ratio in accordance with the Economy and Finance Ministry's Detailed Guidelines for Preparing the 2018 Budget Plan and Fund Management Plan (Manual for Business Type and Item). As a result, it has been expected that Construction Management consideration will be calculated according to a single government standard and that the Criteria will be applied reasonably. In addition, although the change in the Labor Standard Act has a significant effect on the working environment of the construction site, the nature of the construction site is not considered in this Act. Based on these problems, the study suggested that the government should apply a single standard after consultation with the relevant agencies when calculating the consideration for Construction management, that the scope of the Criteria for the Cost of Construction Technology Services should be clear, that the amount of input by the Construction Manager should be considered for the capability of engineers and the number of working days, and that construction characteristics should be considered when determining the number of working days and hours.

• Journal of KIISE:Databases
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• v.33 no.6
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• pp.620-630
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• 2006

Event-detection is an important application of sensor networks. Join operations can facilitate event-detection with a condition table predefined by a user. When join operations are used for event-detection, it is desirable, if possible, to do in-network join processing to reduce communication costs. In this paper, we propose an energy-efficient in-network join algorithm, called PBA. In PBA, each partition of a condition table is stored along the path from each node to the base station, and then in-network joins are performed on the path. Since each node can identify the parts to store in its storage by its level, PBA reduces the cost of disseminating a condition table considerably Moreover, while the existing method does not work well when the ratio of the size of the condition table to the density of the network is a little bit large, our proposed method PBA does not have such a restriction and works efficiently in most cases. The results of experiments show that PBA is efficient usually and especially provides significant cost reduction over existing one when a condition table is relatively large in comparison with the density of the network, or the routing tree of the network is high.