• Journal of the Korean Society of Safety
• /
• v.15 no.3
• /
• pp.66-70
• /
• 2000

In order to cope with environmental problems caused by harmful gases emitted from various industrial sources, a new technology which employs discharge plasma formed in ordinary atmospheric pressure has been intensively investigated in many industrialized nations. Although a plenty of useful outcomes and suggestions have been made public by scientists in this field, few commercial products which effectively decompose pollutant gases have appeared as yet. This is partly because that the energy efficiency of a most effective plasma reactor has not reached a satisfactory level in comparison with those of devices using conventional technologies. In an attempt to solve the problem mentioned above, we noticed to combine heterogeneous electrical discharges. This concepts is based on that each plasma reactor has its specific spatial region in which chemical reaction are active and by electrically affected with another reactor of different type, the activated region would increase - which may lead to cutting down the energy consumption. To prove this concept experimentally, two different discharge equipments, a plane ceramic-based surface discharge electrode and a corona electrode with tungsten needle may, are selected and combined to fabricate a hybrid plasma reactor. The results are summarized as follows; (1) Ozone concentration generated in the plasma region drastically increases when the positive corona discharge is added to the surface discharge. The rate of increase of ozone depends on the frequency of the surface discharge. The negative corona, however, does not contribute to the improvement of the ozone generation. (2) NO(nitrogen monoxide) decomposition rate also improves by simultaneously applying the surface and the positive corona discharges. The effect of the corona superposition is more evident when the level of the surface discharge is moderate. (3) By adjusting the corona level, the net energy efficiency during NO decomposition improves in comparison with the simple surface discharge reactor.

• Journal of Internet Computing and Services
• /
• v.4 no.5
• /
• pp.1-9
• /
• 2003

In this paper, we combine AMC (Adaptive Modulation and Coding) with MIMO (Multiple Input Multiple Output) multiplexing to improve the throughput performance of AMC in Next Generation Communication Mobile Systems. In addition, we propose a system that adopts STD (Selection Transmit Diversity) in the combined system. The received SNR (Signal to Noise Ratio) is improved by adopting STD techniques and an improved SNR increases a probability of selecting MCS (Modulation and Coding Scheme) level that supports higher data rate. The computer simulation is performed in flat Rayleigh fading channel. The results show that higher throughput is achieved by AMC-TD schemes. AMC-STTD scheme shows about 250kbps increase in throughput. And AMC-STD with 2 transmit antennas achieves about 420 kbps throughput improvement over the conventional AMC at 9dB SNR.

• Journal of The Korean Society of Agricultural Engineers
• /
• v.61 no.4
• /
• pp.1-10
• /
• 2019

Unmanned aerial vehicle(UAV) can acquire images with lower cost than conventional manned aircraft and commercial satellites. It has the advantage of acquiring high-resolution aerial images covering in the field area more than 50 ha. The purposes of this study is to develop the rice grain yield distribution using UAV. In order to develop a technology for estimating the rice yield using UAV images, time series UAV aerial images were taken at the paddy fields and the data were compared with the rice yield of the harvesting area for two rice varieties(Singdongjin, Dongjinchal). Correlations between the vegetation indices and rice yield were ranged from 0.8 to 0.95 in booting period. Accordingly, rice yield was estimated using UAV-derived vegetation indices($R^2=0.70$ in Sindongjin, $R^2=0.92$ in Donjinchal). It means that the rice yield estimation using UAV imagery can provide less cost and higher accuracy than other methods using combine with yield monitoring system and satellite imagery. In the future, it will be necessary to study a variety of information convergence and integration systems such as image, weather, and soil for efficient use of these information, along with research on preparing management practice work standards such as pest control and nutrient use based on UAV image information.

• The Korean Journal of Applied Statistics
• /
• v.32 no.1
• /
• pp.1-13
• /
• 2019

An adaptive seamless Phase II/III clinical trial design enables a reduction in the sample size (in comparison to a conventional design) that also shortens the clinical development time. It is also very effective in clinical trials since it can have higher statistical power than Phase III alone. In this study, we use extensive simulation studies to compare several multiple hypothesis testing methods that can help select the best doses in a Phase II study along with several methods to combine p-values of the Phase II and Phase III study.

• Tissue Engineering and Regenerative Medicine
• /
• v.15 no.6
• /
• pp.761-769
• /
• 2018

BACKGROUND: Bioprinting has recently appeared as a powerful tool for building complex tissue and organ structures. However, the application of bioprinting to regenerative medicine has limitations, due to the restricted choices of bio-ink for cytocompatible cell encapsulation and the integrity of the fabricated structures. METHODS: In this study, we developed hybrid bio-inks based on acrylated hyaluronic acid (HA) for immobilizing bio-active peptides and tyramine-conjugated hyaluronic acids for fast gelation. RESULTS: Conventional acrylated HA-based hydrogels have a gelation time of more than 30 min, whereas hybrid bio-ink has been rapidly gelated within 200 s. Fibroblast cells cultured in this hybrid bio-ink up to 7 days showed >90% viability. As a guidance cue for stem cell differentiation, we immobilized four different bio-active peptides: BMP-7-derived peptides (BMP-7D) and osteopontin for osteogenesis, and substance-P (SP) and Ac-SDKP (SDKP) for angiogenesis. Mesenchymal stem cells cultured in these hybrid bio-inks showed the highest angiogenic and osteogenic activity cultured in bio-ink immobilized with a SP or BMP-7D peptide. This bio-ink was loaded in a three-dimensional (3D) bioprinting device showing reproducible printing features. CONCLUSION: We have developed bio-inks that combine biochemical and mechanical cues. Biochemical cues were able to regulate differentiation of cells, and mechanical cues enabled printing structuring. This multi-functional bio-ink can be used for complex tissue engineering and regenerative medicine.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2021.10a
• /
• pp.449-451
• /
• 2021

Cyber-attacks targeting endpoints have developed sophisticatedly into targeted and intelligent attacks, Advanced Persistent Threat (APT) targeting the Industrial Internet of Things (IIoT) has increased accordingly. Machine learning-based Endpoint Detection and Response (EDR) solutions combine and complement rule-based conventional security tools to effectively defend against APT attacks are gaining attention. However, universal EDR solutions have a high false positive rate, and needs high-level analysts to monitor and analyze a tremendous amount of alerts. Therefore, the process of optimizing machine learning-based EDR solutions that consider the characteristics and vulnerabilities of IIoT environment is essential. In this study, we analyze the flow and impact of IIoT targeted APT cases and compare the method of machine learning-based APT detection EDR solutions.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.10 no.12
• /
• pp.2329-2334
• /
• 2006

In this paper, we proposed a method complementing failure of combining DNA fragments, defect of conventional contig assembly programs. In the proposed method, very long DNA sequence data are made into a prototype of fragment of about 700 bases that can be analyzed by automatic sequence analyzer at one time, and then matching ratio is calculated by comparing a standard prototype with 3 fragmented clones of about 700 bases generated by the PCR method. In this process, the time for calculation of matching ratio is reduced by Compute Agreement algorithm. Two candidates of combined fragments of every prototype are extracted by the degree of overlapping of calculated fragment pairs, and then degree of combination is decided using a fuzzy reasoning method that utilizes the matching ratios of each extracted fragment, and A, C, G, T membership degrees of each DNA sequence, and previous frequencies of each A, C, G, T. In this paper. DNA sequence combination is completed by the iteration of the process to combine decided optimal test fragments until no fragment remains. For the experiments, fragments or about 700 bases were generated from each sequence of 10,000 bases and 100,000 bases extracted from 'PCC6803', complete protein genome. From the experiments by applying random notations on these fragments, we could see that the proposed method was faster than FAP program, and combination failure, defect of conventional contig assembly programs, did not occur.

• The Journal of the Acoustical Society of Korea
• /
• v.37 no.1
• /
• pp.12-20
• /
• 2018

Efforts have been made to reconstruct low-resolution underwater images to high-resolution ones by using the image SR (Super-Resolution) method, all to improve efficiency when acquiring side-scan sonar images. As side-scan sonar images are similar with the optical images with respect to exploiting 2-dimensional signals, conventional image restoration methods for optical images can be considered as a solution. One of the most typical super-resolution methods for optical image is a sparse coding and there are studies for verifying applicability of sparse coding method for underwater images by analyzing sparsity of underwater images. Sparse coding is a method that obtains recovered signal from input signal by linear combination of dictionary and sparse coefficients. However, it requires huge computational load to accurately estimate sparse coefficients. In this study, a sparse coding based underwater image super-resolution method is applied while a selective reconstruction method for object region is suggested to reduce the processing time. For this method, this paper proposes an edge detection and object and non object region classification method for underwater images and combine it with sparse coding based image super-resolution method. Effectiveness of the proposed method is verified by reducing the processing time for image reconstruction over 32 % while preserving same level of PSNR (Peak Signal-to-Noise Ratio) compared with conventional method.

• Journal of the Institute of Electronics Engineers of Korea TC
• /
• v.39 no.1
• /
• pp.34-41
• /
• 2002

In the conventional rake receiver structure for the IS-95 CDMA system, each finger has its own time-deskew buffer or FIFO that aligns the multipath signals to the same timing reference in order to combine symbols. This architecture is not a burden to the rake receiver design mainly because of the small number and size of the buffers. However, the number and size of the buffers are significantly increased in the cdma2000 system which adopts multiple carriers and the small spreading gain for a higher rate in data services. In order to decrease the number of buffers, we propose a new model of the time-deskew buffers, which combines the symbols as well as realigns them at the same time. Our architecture reduces the hardware complexity of the buffers by about more than 60% and 70% compared with the conventional one when we consider each rake receiver has three and four independent fingers, respectively. Moreover, the proposed algorithm is very useful not only to the cdma2000 rake receiver but also to the receiver with many fingers in order to increase the BER performance.

• Journal of The Geomorphological Association of Korea
• /
• v.19 no.3
• /
• pp.37-49
• /
• 2012

The objective of this paper is to propose a methodology for surface sediments classification in tidal flats that can combine ground survey data with high-resolution remote sensing data by multivariate kriging. Unlike conventional methodologies that have classified remote sensing data by using pre-classified sediment components, a new classification methodology presented in this paper first generates sediment component fraction maps and then classifies the sediments on a final stage. For generating sediment component fractions, regression kriging, as one of multivariate kriging algorithms, is applied to integrate ground survey data and remote sensing data. First, trend components of sand, silt, and clay are derived through regression analysis of ground survey data and spectral information from remote sensing data. Then, residuals at sample locations are computed and interpolated to generate residual components in the study area. Finally, the sediment component fractions are computed by adding the residuals to the trend components and are classified on a final stage. A case study at the Baramarae tidal flats with KOMPSAT-2 imagery is carried out to evaluate the classification capability of the proposed classification methodology. Through the case study, the proposed methodology showed the best classification accuracy, compared with the conventional classification methodologies. Especially, much improvement of classification accuracy for fine-grained sediments were also obtained. Therefore, it is expected that the presented classification methodology would be an effective one for surface sediments classification in tidal flats.