• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.16 no.10
• /
• pp.3275-3298
• /
• 2022

Cloud-based architectures for precision agriculture are domain-specific controlled and require remote access to process and analyze the collected data over third-party cloud computing platforms. Due to the dynamic changes in agricultural parameters and restrictions in terms of accessing cloud platforms, developing a locally controlled and real-time configured architecture is crucial for efficient water irrigation and farmers management in agricultural fields. Thus, we present a new implementation of an independent sensor-enabled architecture using variety of wireless-based sensors to capture soil moisture level, amount of supplied water, and compute the reference evapotranspiration (ETo). Both parameters of soil moisture content and ETo values was then used to manage the amount of irrigated water in a small-scale agriculture field for 356 days. We collected around 34,200 experimental data samples to evaluate the performance of the architecture under different agriculture parameters and conditions, which have significant influence on realizing real-time monitoring of agricultural fields. In a proof of concept, we provide empirical results that show that our architecture performs favorably against the cloud-based architecture, as evaluated on collected experimental data through different statistical performance models. Experimental results demonstrate that the architecture has potential practical application in a many of farming activities, including water irrigation management and agricultural condition control.

• The Journal of Industrial Distribution & Business
• /
• v.14 no.8
• /
• pp.19-25
• /
• 2023

Using a procurement and construction stage emphasis on the capabilities of the Sub-Contractor (SC), the present research aims to discover the types of unfair activities between the Main Contractor (MC) and SC and their influence on project completion. This research also tries to figure out solutions which can reduce unfair activities between MC and SC. Research design, data and methodology: The qualitative textual analysis was selected for the current research and has been used by numerous previous researchers commonly to review relevant themes in the prior resources and suggested for researchers who conduct a reviewing procedure to analyze meta-analysis approach for figuring out better research findings from prior resources. Results: The result indicates the prevalence and consequences of bid shopping, emphasizing the need for transparency and fair bidding practices. Late payment issues were also found to be crucial for subcontractors' financial stability, urging the implementation of prompt payment legislation and agreements. Conclusions: In conclusion, the research revealed that subcontracting is common in construction projects, with general contractors relying on multiple subcontractors to carry out specific work items. The accomplishment of building projects hinges on the collaborative efforts between the main contractor (MC) and subcontractors (SCs), each focusing on different aspects of the project.

• Wind and Structures
• /
• v.38 no.4
• /
• pp.309-323
• /
• 2024

The gust factor and turbulence intensity are two crucial parameters that characterize the properties of turbulence. In tropical cyclones (TCs), these parameters exhibit significant variability, yet there is a lack of established formulas to account for their probabilistic characteristics with consideration of their inherent connection. On this condition, a probabilistic analysis of gust factors and turbulence intensities of TCs is conducted based on fourteen sets of wind data collected at the Sutong Cable-stayed Bridge site. Initially, the turbulence intensities and gust factors of recorded data are computed, followed by an analysis of their probability densities across different ranges categorized by mean wind speed. The Gaussian, lognormal, and generalized extreme value (GEV) distributions are employed to fit the measured probability densities, with subsequent evaluation of their effectiveness. The Gumbel distribution, which is a specific instance of the GEV distribution, has been identified as an optimal choice for probabilistic characterizations of turbulence intensity and gust factor in TCs. The corresponding empirical models are then established through curve fitting. By utilizing the Gumbel distribution as a template, the nexus between the probability density functions of turbulence intensity and gust factor is built, leading to the development of a generalized probabilistic model that statistically describe turbulence intensity and gust factor in TCs. Finally, these empirical models are validated using measured data and compared with suggestions recommended by specifications.

• Journal of Sericultural and Entomological Science
• /
• v.53 no.2
• /
• pp.87-91
• /
• 2015

There is no specific data on Entomogenous fungus (DongChungHaCho) in accordance with the silkworm varieties, despite of very high value industrial use as functional materials at domestic and abroad. In this study, we investigated culture condition and characteristics of Paecilomyces tenuipes in 3 silkworm cultivars and 2 specific silkworm breeds. Infection rate of P. tenuipes for silkworm varieties was the highest Kumokjam, followed by Baegokjam, Daeseongjam, Golden silk, Yeonnokjam in that order. The optimum culture conditions were as follows: dark condition, $22^{\circ}C{\pm}1$, and about $4cm^2$ in planting density per pupa. Also, we have developed annual production technologies of P. tenuipes. First, in order that the moisture content of the infection pupa became 3% or less in the natural condition. Second, the dried pupa must be vacuum-packed and was kept under $4^{\circ}C$. Finally, by restoring the moisture content of the dried pupa and culture in optimal condition, the technique for annual production of the P. tenuipes was achieved. Therefore, we expect that the use of Kumokjam and annual production technique will contribute significantly to farm income.

• The Bulletin of The Korean Astronomical Society
• /
• v.44 no.1
• /
• pp.54.2-54.2
• /
• 2019

Removing noise which occurs inevitably when taking image data has been a big concern. There is a way to raise signal-to-noise ratio and it is regarded as the only way, image stacking. Image stacking is averaging or just adding all pixel values of multiple pictures taken of a specific area. Its performance and reliability are unquestioned, but its weaknesses are also evident. Object with fast proper motion can be vanished, and most of all, it takes too long time. So if we can handle single shot image well and achieve similar performance, we can overcome those weaknesses. Recent developments in deep learning have enabled things that were not possible with former algorithm-based programming. One of the things is generating data with more information from data with less information. As a part of that, we reproduced stacked image from single shot image using a kind of deep learning, conditional generative adversarial network (cGAN). r-band camcol2 south data were used from SDSS Stripe 82 data. From all fields, image data which is stacked with only 22 individual images and, as a pair of stacked image, single pass data which were included in all stacked image were used. All used fields are cut in $128{\times}128$ pixel size, so total number of image is 17930. 14234 pairs of all images were used for training cGAN and 3696 pairs were used for verify the result. As a result, RMS error of pixel values between generated data from the best condition and target data were $7.67{\times}10^{-4}$ compared to original input data, $1.24{\times}10^{-3}$. We also applied to a few test galaxy images and generated images were similar to stacked images qualitatively compared to other de-noising methods. In addition, with photometry, The number count of stacked-cGAN matched sources is larger than that of single pass-stacked one, especially for fainter objects. Also, magnitude completeness became better in fainter objects. With this work, it is possible to observe reliably 1 magnitude fainter object.

• Journal of the military operations research society of Korea
• /
• v.29 no.2
• /
• pp.61-80
• /
• 2003

A fire sequencing problem is considered. Fire sequencing problem is a kind of scheduling problem that seeks to minimize the overall time span under a result of weapon­target allocation problem. The assigned weapons should impact a target simultaneously and a weapon cannot transfer the firing against another target before all planned rounds are consumed. The computational complexity of the fire sequencing problem is strongly NP­complete even if the number of weapons is two, so it is difficult to get the optimal solution in a reasonable time by the mathematical programming approach. Therefore, a genetic algorithm is adopted as a solution method, in which the representation of the solution, crossover and mutation strategies are applied on a specific condition. Computational results using randomly generated data are presented. We compared the solutions given by CPLEX and the genetic algorithm. Above $7(weapon){\times}15(target)$ size problems, CPLEX could not solve the problem even if we take enough time to solve the problem since the required memory size increases dramatically as the number of nodes expands. On the other hand, genetic algorithm approach solves all experimental problems very quickly and gives good solution quality.

• Proceedings of the IEEK Conference
• /
• 2000.06b
• /
• pp.278-281
• /
• 2000

In this study, the electrical characteristics of 100V -Class LDMOSFET for high temperature applications such as electronic control systems of automobiles and motor driver were investigated. Measurement data are taken over wide range of temperature(300K-500K) and various drift region length(6.6$\mu\textrm{m}$-12.6$\mu\textrm{m}$). In high temperature condition(>450K), drain current decreased over 50％, and specific on-resistance increased about twice in comparison with room temperature. Moreover the ratio R$\sub$on//BV, a figure of merit of the device, increased with increasing temperature.

• Transactions of the Korean Society of Mechanical Engineers
• /
• v.17 no.9
• /
• pp.2214-2222
• /
• 1993

With the use of the NC machine tool, the unmanned production system has been growing recently in the manufacturing field. This there are problems with monitoring adequate tool fracture during the cutting process efficiently. This study was planned and carried out to discover a way of monitoring tool condition in NO-LINE systems during the cutting process. The acquisition of data in cutting force and tool wear has been made in the section examined, to extract the RMS value of the cutting force as specific factors in the cutting process. The fluctuation of the RMS characteristics. From the results, it has been shown that the fluctuation of the RMS values for the cutting force has a close relation to flank wear.

• International Journal of Air-Conditioning and Refrigeration
• /
• v.14 no.1
• /
• pp.28-39
• /
• 2006

Two-phase flow through a T-junction has been studied by numerous researchers so far. The dividing characteristics of the gas and liquid phases at the T-junction are very complicated due to a lot of related variables. The prediction models have been suggested by using experimental data for a specific condition or working fluid. But, they showed the application limitation for the most of the other conditions or fluids. Since most of them are applicable for their own experimental range, the generalized model for the wide range of conditions and fluids is needed. Even though it's not available now, some of the models developed for air-water flow at a T-junction might be applicable for the part of refrigerants with some modifications. Especially, for the two-phase flow of refrigerants at the T-junction, very few studies have been performed. Further experimental study is required to be performed for the wide range of test conditions and fluids to predict properly the two-phase flow distribution and phase separation through the T-junction.

• Journal of the Korean Society of Visualization
• /
• v.8 no.2
• /
• pp.31-39
• /
• 2010

Hysteresis is an effect by which the order of previous events influences the order of subsequent events. Hysteresis phenomenon of supersonic internal flows with shock waves has not yet been clarified satisfactorily. In the present study, experiments are carried out on internal flow in a supersonic nozzle to clarify the hysteresis phenomena for the shock waves. Flow visualization is carried out separately on the straight and divergent channels downstream of the nozzle throat section. Results obtained were compared with numerically simulated data. The results confirmed hysteresis phenomenon for shock wave in the Laval nozzle at a certain specific condition. The relationship between hysteresis phenomenon and the range of the rate of change of pressure ratio with time was shown experimentally. The existence of hysteretic behavior in the formation, both the location and strength, of shock wave in the straight part of the supersonic nozzle with a range of pressure ratio has also been confirmed numerically.