• Journal of Practical Engineering Education
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• v.14 no.1
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• pp.1-10
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• 2022

Learning C programming language in electronics education is an important basic education course for understanding computer programming and acquiring the ability to use microprocessors in embedded systems. In order to focus on understanding basic grammar and algorithms, it is a common teaching method to write programs based on C standard library functions in the console window and learn theory and practice in parallel. However, if a student wants to start a project activity or go to a deeper stage after acquiring some basic knowledge of the C language, using only the C standard library function in the console window limits what a student can express or control with the C program. For the purpose of making it easier for a student to use graphics or multimedia resources and increase educational value, this paper studies a case of applying Simple DirectMedia Layer (SDL), an open source software, into the C programming language learning process. The SDL-based programming course applied after completing the basic programming curriculum performed in the console window is introduced, and the educational value is evaluated through a survey. As a result, more than 56% of the respondents expressed positive opinions in terms of improved application ability, stimulating interest, and overall usefulness, and less than 4% of them had negative opinions.

• Journal of Plant Biotechnology
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• v.49 no.4
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• pp.307-315
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• 2022

Artemisinin is a secondary metabolite of Artemisia annua that shows potent anti-malarial, anti-bacterial, antiviral, and anti-tumor effects. The supply of artemisinin depends on its content in Artemisia annua, in which various environmental factors can affect the plant's biosynthetic yield. In this study, the effects of different light-emitting diode (LED)-irradiation conditions were tested to optimize the germination and growth of Artemisia annua for the enhanced production of artemisinin. Specifically, the ratio between the red and blue lights in the irradiating LED was varied for investigation as follows: [Red : Blue] = [6 : 4], [7 : 3], and [8 : 2]. Furthermore, additional stress factors like UV-B-irradiation (1,395 ㎼/cm²), low temperature (4℃), and dehydration were also explored to induce hormetic expressions of ADS, CYP, and ALDH1, which are essential genes for the biosynthesis of artemisinin. Quantitative polymerase chain reaction (qPCR) was used to analyze the expression levels of the respective genes and their correlation with the specified conditions. [8 : 2] LED-irradiation was the most optimal among the tested conditions for the cultivation of Artemisia annua in terms of both fresh and dry weights post-harvest. For the production of artemisinin, however, [7 : 3] LED-irradiation with dehydration for six hours pre-harvest was the most optimal condition by inducing around twofold enhancement in the biosynthetic yield of artemisinin. As expected, a correlation was observed between the expression levels of the genes and the contents of artemisinin accumulated.

• Journal of the Korean Society of Propulsion Engineers
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• v.26 no.4
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• pp.54-63
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• 2022

A 3-tonf class liquid rocket engine that powers the upper stage of a small launcher and lifts 500 kg payload to 500 km SSO is designed. The small launcher is to utilize the flight-proven technology of the 75-tonf class engine for the first stage. A combination of liquid oxygen and liquid methane has been selected as their cryogenic states can provide an extra boost in specific impulse as well as enable a weight saving via the common dome arrangement. An expander cycle is chosen among others as the low-pressure operation makes it robust and reliable while a specific impulse of over 360 seconds is achievable with the nozzle extension ratio of 120. Key components such as combustion chamber and turbopump are designed for additive manufacturing to a target cost. The engine system provides an evaporated methane for the autogenous pressurization system and the reaction control of the stage. This upper stage propulsion system can be extended to various missions including deep space exploration.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.36 no.3
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• pp.193-201
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• 2023

In this study, a nonlinear truss finite element is developed to analyze structures with negative Poisson effect-induced tensile buckling. In general, the well-known buckling phenomenon is a stability problem under a compressive load, whereas tensile buckling occurs because of local compression caused by tension. It is not as well-known as classical buckling because it is a recent study. The mechanism of tensile buckling can be briefly explained from an energy standpoint. The nonlinear truss finite element with a torsional spring is formulated because the finite element has not been reported in the literature yet. The post-buckling analysis is then performed using the generalized displacement control method, which reveals that the torsional spring plays an important role in tensile buckling. Structures that mimic a negative Poisson effect can be constructed using such post-buckling behaviors, and one of the possible applications is a mechanical switch. The results obtained are compared to those of analytical solutions and commercial finite element analysis to assess the validity of the proposed finite element model. The numerical results show that the developed finite element model could be a viable option for the basic design of nonlinear structures with a negative Poisson effect.

• Journal of Venture Innovation
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• v.5 no.2
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• pp.85-99
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• 2022

Dryers becoming commercially available for experimental and industrial use are classified to general drying oven, hot-air dryer, vacuum dryer, freezing dryer, etc. and kinds of them are various from the function, size and volume, etc. But the moisture measurement is not applied although it is important factor for the quality control and the performance improvement of products, and then now is very passive because the weight is weighed arbitrarily after dry-end. Generally the method for measuring moisture is divided by a direct measurement method and a indirect measurement method, and the former such as the change of weight or volume on the front and rear of separation of moisture, etc. is mainly used. Relatively a indirect measurement is very limited to apply due to utilize measurement apparatuses using temperature conductivity and micro-wave etc. In this research, we easily designed the moisture measurement system using the open-source based Arduino, and monitored moisture fluctuations and weight profiles in the real-time without the effect of external environment. Concretely the temperature-humidity and load cell sensors were packaged into a drying oven and the various change values were measured, and their sensors capable to operate 60℃ and 80℃ were selected to suitable for the moisture sensitive materials and the food dry. And also the performance safety using the organic samples of banana, pear, sawdust could be secured because the changes of evaporation rate as the dry time and temperature, and the measurement values of load cell appeared stable response characteristics through repeated experiments. Hereafter we judge that the reliability can be improved increasingly through the expansion of temperature-humidity range and the comparative analysis with CFD(Computational Fluid Dynamics) program.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.22 no.5
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• pp.182-199
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• 2023

Since 2021, government departments have been promoting Automated Driving Technology Development and Innovation Project as national research and development(R&D) project. The automated vehicles and service technologies developed as part of these projects are planned to be subsequently provided to the public at the selected Living Lab City. Therefore, it is important to determine a spatial area and operation section that enables safe and stable automated driving, depending on the purpose and characteristics of the target service. In this study, the static Operational Design Domain(ODD) elements for Level 4 automated driving services were reclassified by reviewing previously published papers and related literature surveys and investigating field data. Spatial analysis techniques were used to consider the reclassified ODD elements for level 4 in the real area of level 3 automated driving services because it is important to reflect the spatial factors affecting safety related to real automated driving technologies and services. Consequently, a total of six driving mode changes(disengagement) were derived through spatial information analysis techniques, and the factors affecting the safety of automated driving were crosswalk, traffic light, intersection, bicycle road, pocket lane, caution sign, and median strip. This spatial factor analysis method is expected to be useful for determining special areas for the automated driving service.

• Korean journal of applied entomology
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• v.62 no.4
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• pp.333-343
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• 2023

King oyster mushrooms are one of the major fresh agricultural products which their exports are increasing every year in Korea. Lycoriella ingenua, is notorious insect pest in agriculture, especially in mushroom production. Larvae of L. ingenua cause mainly direct crop damage and adults are vectors of several dangerous fungal pathogens. In this study, the effects of electron beam, X-ray, and gamma-ray irradiation on the development and reproduction of L. ingenua were evaluated. In addition, to find the optimal dose to control L. ingenua in a box filled with king oyster mushrooms, an empirical experiment was conducted for each radiation. As a result, the development and reproduction of L. ingenua were inhibited at 50 Gy for all electron beam, X-ray, and gamma-ray irradiation. Additionally, at the top, middle, and bottom of the export box filled with king oyster mushrooms, the development and reproduction of L. ingenua were inhibited by electron beam with 150 Gy, X-ray with 100 Gy, and gamma-ray with 50 Gy. These results can be provided as basic data for establishing an integrated quarantine management system when exporting mushrooms. It will also contribute to the safety of agricultural products and the strengthening of export competitiveness.

• Information Systems Review
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• v.24 no.4
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• pp.119-142
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• 2022

Organizations are attempting a digital transformation that converts physical business processing into virtual business processing. Through this digital transformation, organizations are overcoming time and space constraints and creating competitiveness. The digital transformation of this work environment has been accelerated as many organizations have implemented remote work due to the recent COVID-19 pandemic. This study focused on business process virtualizability, which is the result of the rapid digital transformation of the work environment. Business process virtualizability is the resulting quality, such as the suitability or excellence of business processing in a virtual environment. This research model is the effect of process, IT and organizational characteristics on business process virtualizability. As a result of the verification of people who have experienced remote work in a virtual environment, first, it was confirmed that, in terms of process characteristics, sensory requirements affect business process virtualizability, but relationship requirements, synchronism requirements, and identification and control requirements do not. Second, in terms of IT characteristics, it was confirmed that representation and reach affect business process virtualizability. Third, it was confirmed that, in terms of organizational characteristics, job autonomy affects business process virtualizability, but evaluation unfairness does not. This study found that representation and reach of IT had the most significant influence on business process virtualizability, job autonomy was next, and sensory requirements had the lowest influence. This presents practical implications for organizations to increase the success potential of business process virtualizability.

• The Journal of the Acoustical Society of Korea
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• v.26 no.6
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• pp.250-258
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• 2007

Current speech recognition technology s achieved high performance with the development of hardware devices, however it is insufficient for some applications where high reliability is required, such as voice control of powered wheelchairs for disabled persons. For the system which aims to operate powered wheelchairs safely by voice in real environment, we need to consider that non-voice commands such as user s coughing, breathing, and spark-like mechanical noise should be rejected and the wheelchair system need to recognize the speech commands affected by disability, which contains specific pronunciation speed and frequency. In this paper, we propose non-voice rejection method to perform voice/non-voice classification using both YIN based fundamental frequency(F0) extraction and reliability in preprocessing. We adopted a multi-template dictionary and acoustic modeling based speaker adaptation to cope with the pronunciation variation of inarticulately uttered speech. From the recognition tests conducted with the data collected in real environment, proposed YIN based fundamental extraction showed recall-precision rate of 95.1% better than that of 62% by cepstrum based method. Recognition test by a new system applied with multi-template dictionary and MAP adaptation also showed much higher accuracy of 99.5% than that of 78.6% by baseline system.

• The Journal of the Acoustical Society of Korea
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• v.29 no.3
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• pp.191-199
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• 2010

Physical modeling is a synthesis method of high quality sound which is similar to real sound for musical instruments. However, since physical modeling requires a lot of parameters to synthesize sound of a musical instrument, it prevents real-time processing for the musical instrument which supports a large number of sounds simultaneously. To solve this problem, this paper proposes a single instruction multiple data (SIMD) parallel processor that supports real-time processing of sound synthesis of guitar, a representative plucked string musical instrument. To control six strings of guitar, we used a SIMD parallel processor which consists of six processing elements (PEs). Each PE supports modeling of the corresponding string. The proposed SIMD processor can generate synthesized sounds of six strings simultaneously when a parallel synthesis algorithm receives excitation signals and parameters of each string as an input. Experimental results using a sampling rate 44.1 kHz and 16 bits quantization indicate that synthesis sounds using the proposed parallel processor were very similar to original sound. In addition, the proposed parallel processor outperforms commercial TI's TMS320C6416 in terms of execution time (8.9x better) and energy efficiency (39.8x better).