• Journal of the Korea Society of Computer and Information
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• v.25 no.4
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• pp.165-172
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• 2020

In this paper we propose an uses on-device-based edge computing technology and big data analysis methods through the use of on-device-based edge computing technology and analysis of big data, which are distributed computing paradigms that introduce computations and storage devices where necessary to solve problems such as transmission delays that occur when data is transmitted to central centers and processed in current general smart factories. However, even if edge computing-based technology is applied in practice, the increase in devices on the network edge will result in large amounts of data being transferred to the data center, resulting in the network band reaching its limits, which, despite the improvement of network technology, does not guarantee acceptable transfer speeds and response times, which are critical requirements for many applications. It provides the basis for developing into an AI-based facility prediction conservation analysis tool that can apply deep learning suitable for big data in the future by supporting intelligent facility management that can support productivity growth through research that can be applied to the field of facility preservation and smart factory industry with integrated hardware technology that can accommodate these requirements and factory management and control technology.

• The Journal of Korean Institute of Information Technology
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• v.15 no.12
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• pp.157-164
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• 2017

Mobile ECG signal measurement is a technique to measure small signals of several mV, and many studies have been conducted to remove noise including wandering scheme. Removal of the equipotential line noise caused by shaking or movement of the electrode cable is one of the core research contents for the electrocardiogram measurement. In this study, we proposed a modified step-size of combined NLMS(normalized least squares) and DLMS(delayed least squares) adaptive filter to eliminate baseline noise from ECG signals. The proposed method mainly adjusts initial filter step-size to reduce distortion of original ECG signals characteristic after eliminating baseline noise. The modified filter step-size is scaled by filter order size and distortion minimization factor. This method is suitable for portable ECG device with a small processor and less power consumption. This technique also decreases computation time which is essential for real-time filtering. The proposed filter also increase the signal to noise ratio (SNR) compared to conventional NLMS filter.

• KIPS Transactions on Computer and Communication Systems
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• v.10 no.7
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• pp.191-198
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• 2021

Since the size of training dataset become large and the model is getting deeper to achieve high accuracy in deep learning, the deep neural network training requires a lot of computation and it takes too much time with a single node. Therefore, distributed deep learning is proposed to reduce the training time by distributing computation across multiple nodes. In this study, we propose hybrid allreduce strategy that considers the characteristics of each layer and communication and computational overlapping technique for synchronization of distributed deep learning. Since the convolution layer has fewer parameters than the fully-connected layer as well as it is located at the upper, only short overlapping time is allowed. Thus, butterfly allreduce is used to synchronize the convolution layer. On the other hand, fully-connecter layer is synchronized using ring all-reduce. The empirical experiment results on PyTorch with our proposed scheme shows that the proposed method reduced the training time by up to 33% compared to the baseline PyTorch.

• Journal of Environmental Impact Assessment
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• v.28 no.3
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• pp.275-286
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• 2019

In order to prevent local extinction of organisms and to preserve biodiversity, it is important to ensure connectivity between habitats. Even if the habitat is exposed to various disturbance factors, it is possible to avoid or respond to disturbances if they are linked to other habitats. Habitat connectivity can be assessed from a variety of perspectives, but the importance of functional connectivity based on species movement has been emphasized in recent years due to the development of computational capabilities and related software. Among them, Circuitscape, which is a connectivity evaluation tool, has an advantage it can provide detailed reference data for the city planning because it maps ecological flows on individual grid based on circuit theory. Therefore, in this study, the functional connectivity of Suwon was evaluated by applying Circuitscape and then, the ecological corridor to be conserved and supplemented was suggested based on it. The results of this study are expected to effectively complement the methodology related ecological corridor/axis, which was previously provided only in the form of a diagram, and to be effective in management of development project and urban planning.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.3
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• pp.100-109
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• 2019

Maintainability indicates the extent to which maintenance can be done easily and quickly. The consideration of maintainability is crucial to reduce the operation and support costs of weapon systems, but if the maintainability is evaluated after the prototype production is done and necessitates design changes, it may increase the cost and delay the schedule. The evaluation should verify whether maintenance work can be performed, and support the designers in developing a design to improve maintainability. In previous studies, the maintainability index was calculated using the graph theory at the early design phase, but evaluation accuracy appeared to be limited. Analyzing the methods of evaluating the maintainability using fuzzy logic and 3D modeling indicate that the design of a system with good maintainability should be done in an integrated manner during the whole system life cycle. This paper proposes a method to evaluate maintainability using SysML-based modeling and simulation technique and fuzzy logic. The physical design structure with maintainability attributes was modeled using SysML 'bdd' diagram, and the maintainability was represented by an AHP matrix for maintainability attributes. We then calculated the maintainability using AHP-based weighting calculation and fuzzy logic through the use of SysML 'par' diagram that incorporated MATLAB. The proposed maintainability model can be managed efficiently and consistently, and the state of system design and maintainability can be analyzed quantitatively, thereby improving design by early identifying the items with low maintainability.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.12 no.2
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• pp.21-34
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• 2002

In this paper we propos a new hardware architecture of modular exponentiation using a division chain method which has been proposed in (2). Modular exponentiation using the division chain is performed by receding an exponent E as a mixed form of multiplication and addition with divisors d=2 or $d=2^I +1$ and respective remainders r. This calculates the modular exponentiation in about $1.4log_2$E multiplications on average which is much less iterations than $2log_2$E of conventional Binary Method. We designed a linear systolic array multiplier with pipelining and used a horizontal projection on its data dependence graph. So, for k-bit key, two k-bit data frames can be inputted simultaneously and two modular multipliers, each consisting of k/2+3 PE(Processing Element)s, can operate in parallel to accomplish 100% throughput. We propose a new encoding scheme to represent divisors and remainders of the division chain to keep regularity of the data path. When it is synthesized to ASIC using Samsung 0.5 um CMOS standard cell library, the critical path delay is 4.24ns, and resulting performance is estimated to be abort 140 Kbps for a 1024-bit data frame at 200Mhz clock In decryption process, the speed can be enhanced to 560kbps by using CRT(Chinese Remainder Theorem). Futhermore, to satisfy real time requirements we can choose small public exponent E, such as 3,17 or $2^{16} +1$, in encryption and verification process. in which case the performance can reach 7.3Mbps.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.21 no.1
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• pp.153-166
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• 2011

Recent trends in mobile device market whose services are rapidly expanding to provide wireless internet access are drawing people's attention to mobile security. Especially, since threats to information leakage are reaching to the critical level due to the frequent interchange of important data such as personal and financial information through wireless internet, various encryption algorithms has been developed to protect them. The encryption algorithms confront the serious threats by the appearance of side channel attack (SCA) which uses the physical leakage information such as timing, and power consumption, though the their robustness to threats is theoretically verified. Against the threats of SCA, researches including the performance and development direction of SCA should precede. Among tile SCA methods, the power analysis (PA) attack overcome this misalignment problem. The conventional methods require large computational power and they do not effectively deal with the delay changes in a power trace. To overcome the limitation of the conventional methods, we proposed a novel alignment method using peak matching. By computer simulations, we show the advantages of the proposed method compared to the conventional alignment methods.

• KIPS Transactions on Software and Data Engineering
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• v.11 no.4
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• pp.163-168
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• 2022

As cloud computing and the Internet of things are getting popular, the number of devices in the Internet of things computing environments is increasing. In addition, there exist various Internet-based applications, such as home automation and healthcare. In turn, existing studies explored the quality of service, such as downtime and reliability of tasks for Internet of things applications. To enhance the quality of service of Internet of things applications, cloud-fog computing (combining cloud computing and edge computing) can be used for offloading burdens from the central cloud server to edge servers. However, when devices inherit the mobility property, continuity and the quality of service of Internet of things applications can be reduced. In this paper, we propose a resource management scheme based on live migrations for mobility support in edge-based fog computing environments. The proposed resource management algorithm is based on the mobility direction and pace to predict the expected position, and migrates tasks to the target edge server. The performance results show that our proposed resource management algorithm improves the reliability of tasks and reduces downtime of services.

• Journal of the Mineralogical Society of Korea
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• v.19 no.3 s.49
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• pp.171-187
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• 2006

The status of heavy metal contamination was investigated using chemical analyses of stream waters and sediments obtained from Samsanjeil and Sambong Cu mining area in Goseong-gun, Gyeongsangnam-do. In addition, the degree and the environmental risk of heavy metal contamination in stream sediments was assessed through pollution index (Pl) and danger index (DI) based on total digestion by aqua regia and fractionation of heavy metal contaminants by sequential extraction, respectively. Not only the degree of heavy metal contamination was significantly higher in Samsanjeil area than in Sambong area, but its environmental risk was also revealed much more serious in Samsanjeil area than in Sambong area. The differences in status and level of contamination and environmental risk between both two mining areas may be attributed to existence of contamination source and geology. Acid mine drainage is continuously discharged and flows into the stream in Samsanjeil mining area, and it makes the heavy metal contamination in the stream more deteriorated than in Sambong mining area in which acid mine drainage is not produced. In addition, the geology of Samsanjeil mining area is mainly comprised of andesitic rocks including a small amount of calcite and having lower pH buffering capacity fer acid mine drainage, and it is likely that the heavy metal contamination cannot be naturally attenuated in streams. On the contrary, the main geology of Sambong mining area consists of pyroclastic sedimentary Goseong formation containing a high content of carbonates, particularly calcite, and it seems that these carbonates of high pH buffering capacity prevent the heavy metal contamination from proceeding downstream in stream within that area.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.68 no.4
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• pp.438-444
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• 2023

Italian ryegrass (Lolium multiflorum Lam.; IRG) sowing season is delayed due to the autumn rainy season. Therefore, to address this problem, transplanting date and plant density were investigated. Transplant times investigated were October 20th, October 30th, and November 10th and planting densities were 50, 70, and 80 hills per 3.3 m². The plant height, leaf area index, and plant coverage rate were high in the following order: October 20th, October 30th, and November 10th. There was no significant difference among planting densities. In addition, the number of tillers and dry weight before and after wintering were high on October 20th. In terms of yield components, the number of tillers, dry weight, and seed yield per unit area were higher with the transplanting date of October 20th than with transplanting on November 10th. There was no difference in seed yield between the planting densities of 80 and 70 hills per 3.3 m². However, seed yield was low at 50 hills per 3.3 m². In conclusion, the transplanting time for stable seed production is late October, and optimal plant density is 70 and 80 hills per 3.3 m². A stable interplanting number before wintering will contribute to the seed yield.