• 한국연소학회:학술대회논문집
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• 2015.12a
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• pp.23-24
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• 2015

In this talk, we will present what we believe is the state-of-the-art of the numerical modeling and simulation of the combustion processes as they relate to typical scramjet engines. The free-stream Mach number is hypersonic, but the speed is not sufficiently decelerated at the inlet/isolator, as in ramjets, so that combustion takes place under supersonic conditions. This creates some difficulties for most turbulence-combustion models. We delve into the details of these problems, by discussing the software programs that have a long track record for scramjet combustion simulation; with a focus on the accuracy of the baseline numerical methods used, the turbulence modeling/simulation approach, the comparative fidelity of the turbulence-combustion interaction models, ability to simulate premixed/non-premixed/partially-premixed, quenching/re-ignition capabilities, the numerical spark-plug method, Damkholer number regimes supported, and the effects of variable Prandtl, Schmidt, and Lewis numbers. Validation results from high-speed and low-speed combustion applications will also be presented.

• Journal of Astronomy and Space Sciences
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• v.21 no.1
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• pp.29-38
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• 2004

A ultra low noise Q-band HEMT receiver for VLBI has been developed using a local oscillator with a very high phase stability. The performance of receiver was verified by comparison with receivers which were developed at the other countries. The receiver noise temperature shows 65 K in the frequency ragne from 42 ㎓ to 44 ㎓, less than 100 K from 39 ㎓ to 46 ㎓, respectively. A receiver noise temperature at SiO major line of 43㎓ which will be mainly observed by using this receiver has been optimized.

• Current Research on Agriculture and Life Sciences
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• v.30 no.2
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• pp.97-104
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• 2012

Over the last century, drainage systems have become an integral component of agriculture. Climate observations and experiments using General circulation models suggest an intensification of the hydrologic cycle due to climate change. This study presents hydrologic simulations assessing the potential impact of climate change on subsurface drainage in Daegu, Republic of Korea. Historical and Long Ashton Research Station weather generator perturbed future climate data from 15 general circulation models for a field in Daegu were ran into a water management simulation model, DRAINMOD. The trends and variability in rainfall and Soil Excess Water ($SEW_{30}$) were assessed from 1960 to 2100. Rainfall amount and intensity were predicted to increase in the future. The predicted annual subsurface drainage flow varied from -35 to 40 % of the baseline value while the $SEW_{30}$ varied from -50 to 100%. The expected increases in subsurface drainage outflow require that more attention be given to soil and water conservation practices.

• The Bulletin of The Korean Astronomical Society
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• v.43 no.2
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• pp.48.1-48.1
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• 2018

We report on a series of science articles presented in the Children's magazine 고래가그랬어. The monthly articles (appearing since 2016) highlight current issues in Physics and Astronomy with particular emphasis on science being conducted in Korea. Reporting is performed by interviewing experts in their respective fields. In an effort to encourage children to envisage themselves as scientists, interviews are taken predominantly from Korean early-career researchers. Gender balance is obtained through a careful selection of interviewees ensuring that children are exposed to a broad cross-section of science researchers. This series has introduced children to the 1st detection of Gravitational Waves, the KMTnet telescope system, the Korean Very Long Baseline Interferometric Network, KGMT, IBS Axion experiments, and many other experiments and discoveries.

• Publications of The Korean Astronomical Society
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• v.37 no.1
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• pp.1-11
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• 2022

During the course of analysing both single-dish and very long baseline interferometry (VLBI) data obtained from the Korean VLBI Network (KVN), we found a systematic offset between flux density measurements from different antennas. We were able to attribute a majority of the systematic offsets to changes in the "a priori" antenna gains, which were found to have varied up to 10 percent at 22 GHz and up to 30 percent at 43 GHz. Using historical calibrator observations, we present a revised set of gains that may be applied to KVN data taken from 2015 August to 2019 January. Application of the revised gains to the KVN results in a consistency of correlated flux density measurements between the three baselines of approximately five percent. We found that images from the recalibrated data typically have a 50 percent higher dynamic range, with some cases showing an increase of dynamic range of up to a factor of three.

• Proceedings of the National Institute of Ecology of the Republic of Korea
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• v.3 no.3
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• pp.178-186
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• 2022

In order to support biomimicry technology development, it is necessary to develop an omnidirectional service platform which can recommend principles of biomimicry and business ideas, providing experts' networks and carrying out their relevant education and promotion on the ground of baseline data and application research materials related to biomimicry. This study was conducted to establish any probable plans for construction and utilization of the future open-platform which will collect and serve the technology of biomimicry. Accordingly, biological and ecological information databases were examined along with the appreciation of construction and management of major biomimicry DB, and, based on the materials from the interview of related experts, a customer journey map was schematized. Lastly, in order to suggest a mid-to-long-term target-model, the roles of a future biomimicry knowledge service-platform were determined along with the potential plans for its construction and management based on case analysis and customers' needs.

• Journal of Information Processing Systems
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• v.18 no.3
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• pp.344-358
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• 2022

Text summarization is the task of producing a shorter version of a long document while accurately preserving the main contents of the original text. Abstractive summarization generates novel words and phrases using a language generation method through text transformation and prior-embedded word information. However, newly coined words or out-of-vocabulary words decrease the performance of automatic summarization because they are not pre-trained in the machine learning process. In this study, we demonstrated an improvement in summarization quality through the contextualized embedding of BERT with out-of-vocabulary masking. In addition, explicitly providing precise pointing and an optional copy instruction along with BERT embedding, we achieved an increased accuracy than the baseline model. The recall-based word-generation metric ROUGE-1 score was 55.11 and the word-order-based ROUGE-L score was 39.65.

• The Journal of Korea Robotics Society
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• v.18 no.1
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• pp.48-52
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• 2023

Many studies have been conducted to ensure that Visual Place Recognition is reliable in various environments, including edge cases. However, existing approaches use visible imaging sensors, RGB cameras, which are greatly influenced by illumination changes, as is widely known. Thus, in this paper, we use an invisible imaging sensor, a long wave length infrared camera (LWIR) instead of RGB, that is shown to be more reliable in low-light and highly noisy conditions. In addition, although the camera sensor used to solve this problem is an LWIR camera, but since the thermal image is converted into RGB image the proposed method is highly compatible with existing algorithms and databases. We demonstrate that the proposed method outperforms the baseline method by about 0.19 for recall performance.

• Korea Trade Review
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• v.46 no.2
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• pp.93-106
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• 2021

This study analyzes trade communication methods by comparing and analyzing payment methods and procedures of L/C and BPO transactions. As a result of the study, BPO transaction is validated based on the combination results of the confirmed baseline and data set unlike the L/C transaction. Therefore, BPO is superior to L/C transaction in that there is no confrontation between the parties over the matching results. And it can proceed with certain transaction that is paid first and proved later. In addition, the process of accepting data mismatches results in a confirmation of the payment commitment considering the intention of the importer. This allows flexible disposition of documents in response to the post payment situation as long as the documents are held by the exporter, which can be said to be superior to the L/C transaction.

• Journal of Periodontal and Implant Science
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• v.44 no.4
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• pp.169-177
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• 2014

Purpose: We aimed to investigate the impact of nonsurgical periodontal treatment combined with one-year dietary supplementation with omega (${\omega}$)-3 on the serum levels of eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), docosapentaenoic acid (DPA), and arachidonic acid (AA). Methods: Fifteen patients with chronic generalized periodontitis were treated with scaling and root planing. The test group consisted of seven patients ($43.1{\pm}6.0$ years) supplemented with ${\omega}$-3, consisting of EPA plus DHA, three capsules, each of 300 mg of ${\omega}$-3 (180-mg EPA/120-mg DHA), for 12 months. The control group was composed of eight patients ($46.1{\pm}11.6$ years) that took a placebo capsule for 12 months. The periodontal examination and the serum levels of DPA, EPA, DHA, and AA were performed at baseline (T0), and 4 (T1), and 12 (T2) months after therapy. Results: In the test group, AA and DPA levels had been reduced significantly at T1 (P<0.05). AA and EPA levels had been increased significantly at T2 (P<0.05). The ${\Delta}EPA$ was significantly higher in the test compared to the placebo group at T2-T0 (P=0.02). The AA/EPA had decreased significantly at T1 and T2 relative to baseline (P<0.05). Conclusions: Nonsurgical periodontal treatment combined with ${\omega}$-3 supplementation significantly increased the EPA levels and decreased the AA/EPA ratio in serum after one year follow-up. However, no effect on the clinical outcome of periodontal therapy was observed.