• International Journal of Computer Science & Network Security
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• 제21권1호
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• pp.143-151
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• 2021

The enormous prevalence of transferring official confidential digital documents via the Internet shows the urgent need to deliver confidential messages to the recipient without letting any unauthorized person to know contents of the secret messages or detect there existence . Several Steganography techniques such as the least significant Bit (LSB), Secure Cover Selection (SCS), Discrete Cosine Transform (DCT) and Palette Based (PB) were applied to prevent any intruder from analyzing and getting the secret transferred message. The utilized steganography methods should defiance the challenges of Steganalysis techniques in term of analysis and detection. This paper presents a novel and robust framework for color image steganography that combines Linear Congruential Generator (LCG), simulated annealing (SA), Cesar cryptography and LSB substitution method in one system in order to reduce the objection of Steganalysis and deliver data securely to their destination. SA with the support of LCG finds out the optimal minimum sniffing path inside a cover color image (RGB) then the confidential message will be encrypt and embedded within the RGB image path as a host medium by using Cesar and LSB procedures. Embedding and extraction processes of secret message require a common knowledge between sender and receiver; that knowledge are represented by SA initialization parameters, LCG seed, Cesar key agreement and secret message length. Steganalysis intruder will not understand or detect the secret message inside the host image without the correct knowledge about the manipulation process. The constructed system satisfies the main requirements of image steganography in term of robustness against confidential message extraction, high quality visual appearance, little mean square error (MSE) and high peak signal noise ratio (PSNR).

• 보건행정학회지
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• 제30권4호
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• pp.522-530
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• 2020

Background: In 2008, Korea implemented a new type of social insurance known as "long-term care insurance". We examined the association between ownership of long-term care facilities and the incidence of pressure ulcers after the implementation of "long-term care insurance". This study is a population-based retrospective cohort study from 2006 to 2013. Methods: We used medical claims data from the Korean National Health Insurance Corporate Elderly Cohort Database from 2006 to 2013. These data comprise a nationally representative sample. To avoid confounders, only patients admitted to one long-term care facility and who stayed for >70% of the follow-up time were included; as a result, 3,107 individuals were enrolled. The main independent variable was the operating entity of the long-term care facility (local government, corporate bodies, and private for-profit owners), and the dependent variable was the 1-year incidence of pressure-ulcers. Survival analysis (Cox proportional hazard model) was used as an analysis method. Results: Compared to patients admitted to local government long-term care facilities, patients admitted to private long-term care facilities had a significantly higher 1-year risk of pressure ulcers (hazard ratio [HR], 1.94; 95% confidence interval [CI], 1.29-2.91); the risk was especially high among patients who were cognitively dependent (HR, 2.34; 95% CI, 1.25-4.37). Conclusion: Patients admitted to private for-profit long-term care facilities were more likely to have pressure ulcers compared to those in local government and corporate body long-term care facilities. Appropriate assessment tools and publicly available information, as well as more restricted legal requirements, are needed to improve the care quality and outcomes of patients in long-term care facilities.

• Earthquakes and Structures
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• 제20권3호
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• pp.325-335
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• 2021

The majority of Turkey's geography is at risk of earthquakes. Within the borders of Turkey, including the two major active faults contain the North-Eastern and Eastern Anatolia, earthquake, threatening the safety of life and property. On January 24, 2020, an earthquake of magnitude 6.8 occurred at 8:55 p.m. local time. According to the data obtained from the stations in the region, peak ground acceleration in the east-west direction was measured as 0.292 g from the 2308 coded station in Sivrice. It is thought that the earthquake with a magnitude of Mw 6.8 was developed on the Sivrice-Puturge segment of the Eastern Anatolian Fault, which is a left lateral strike slip fault, and the tear developed in an area of 50-55 km. Aftershocks ranging from 0.8 to 5.1 Mw occurred following the main shock on the Eastern Anatolian Fault. The earthquake caused severe structural damages in Elazığ and neighboring provinces. As a result of the field investigations carried out in this study, significant damage levels were observed in the buildings since it did not meet the criteria in the earthquake codes. Within the study's scope, the structural damage cases in reinforced concrete and masonry structures were investigated. Many structural deficiencies and mistakes such as non-ductile details, poor concrete quality, short columns, strong beams-weak columns mechanism, large and heavy overhangs, masonry building damages and inadequate reinforcement arrangements were observed. Requirements of seismic codes are discussed and compared with observed earthquake damage.

• International Journal of Computer Science & Network Security
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• 제22권8호
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• pp.75-80
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• 2022

In modern society, the organization of the educational process plays an important role in education. Traditionally, it is through communication and dialogue between the teacher and the student that professional competence is acquired. As society develops, the demand in the global labor market changes and the requirements and criteria for specialists increase. Therefore, a new approach to managing the pedagogical interaction between a teacher and a student in the process of education in a higher educational institution allows a positive impact on the system of training specialists and opens up new prospects for the formation of competitive specialists. The issue of the quality of education is a key one and is covered in the documents regulating the process of educational activities. Also an important problem today is the transition to qualitatively new and innovative systems of training specialists and the departure from outdated models of managing pedagogical interaction in higher education institutions. The process of managing the pedagogical interaction between a teacher and a student is one of the most important for studying in the context of higher education. Thus, the main task of the study is to analyze the role of communication and dialogue during studies in higher education. As a result of the study, current trends and prerequisites for communication and dialogue tools during studies in higher education

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제15권11호
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• pp.4244-4274
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• 2021

The utilization of UAVs in various fields has led to the development of flying ad hoc network (FANET) technology. In a network environment with highly dynamic topology and frequent link changes, the traditional routing technology of FANET cannot satisfy the new communication demands. Traditional routing algorithm, based on geographic location, can "fall" into a routing hole. In view of this problem, we propose a geolocation routing protocol based on multi-agent reinforcement learning, which decreases the packet loss rate and routing cost of the routing protocol. The protocol views each node as an intelligent agent and evaluates the value of its neighbor nodes through the local information. In the value function, nodes consider information such as link quality, residual energy and queue length, which reduces the possibility of a routing hole. The protocol uses global rewards to enable individual nodes to collaborate in transmitting data. The performance of the protocol is experimentally analyzed for UAVs under extreme conditions such as topology changes and energy constraints. Simulation results show that our proposed QLGR-S protocol has advantages in performance parameters such as throughput, end-to-end delay, and energy consumption compared with the traditional GPSR protocol. QLGR-S provides more reliable connectivity for UAV networking technology, safeguards the communication requirements between UAVs, and further promotes the development of UAV technology.

• International Journal of Computer Science & Network Security
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• 제22권9호
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• pp.287-299
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• 2022

The article deals with the formation of managerial competence of the future head of preschool education institution by means of information and communication technology as a prerequisite for his ability to act competently and objectively evaluate actions and understand the interaction of forms and content of preschool education. The article aimed to study the effectiveness of information and communication technologies in the formation of managerial competence of the future head of preschool education institution. To achieve the objectives, the methods of comparative and systematic analysis were used to compare different views on the problem under study, namely, the formation of managerial competence of the future head of preschool education institution by means of information and communication technologies. The authors of the article determined that the use of information and communication technologies in the preparation of future heads of preschool educational institutions is of great importance and is an indicator in the structure of managerial competence. The priority directions of the use of various software products for the study of the modern Ukrainian language, methods of teaching the Ukrainian language contribute to the intensification of learning material. It is noted that the current state of development of information technologies and their widespread use in education satisfies the requirements of the objectivity of the assessment obtained the quality of the control process of forming the managerial competence of the future leader in the context of the general problems of pre-school education. It is noted that the means of information and communication technologies play a leading role in creating new educational policies and projects, as they motivate the way of access to knowledge.

• Wind and Structures
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• 제34권1호
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• pp.43-58
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• 2022

The BARC flow is studied via Direct Numerical Simulation at a relatively low turbulent Reynolds number, with focus on the geometrical representation of the leading-edge (LE) corners. The study contributes to further our understanding of the discrepancies between existing numerical and experimental BARC data. In a first part, rounded LE corners with small curvature radii are considered. Results show that a small amount of rounding does not lead to abrupt changes of the mean fields, but that the effects increase with the curvature radius. The shear layer separates from the rounded LE at a lower angle, which reduces the size of the main recirculating region over the cylinder side. In contrast, the longitudinal size of the recirculating region behind the trailing edge (TE) increases, as the TE shear layer is accelerated. The effect of the curvature radii on the turbulent kinetic energy and on its production, dissipation and transport are addressed. The present results should be contrasted with the recent work of Rocchio et al. (2020), who found via implicit Large-Eddy Simulations at larger Reynolds numbers that even a small curvature radius leads to significant changes of the mean flow. In a second part, the LE corners are fully sharp and the exact analytical solution of the Stokes problem in the neighbourhood of the corners is used to locally restore the solution accuracy degraded by the singularity. Changes in the mean flow reveal that the analytical correction leads to streamlines that better follow the corners. The flow separates from the LE with a lower angle, resulting in a slightly smaller recirculating region. The corner-correction approach is valuable in general, and is expected to help developing high-quality numerical simulations at the high Reynolds numbers typical of the experiments with reasonable meshing requirements.

• Current Optics and Photonics
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• 제6권2호
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• pp.171-182
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• 2022

A single-photon laser and mid-wave infrared (MWIR) common aperture optical system was designed and developed to detect and range a long-distance civil aviation aircraft. The secondary mirror of the Ritchey-Chretien (R-C) optical system was chosen as a dichroic lens to realize the design of a common aperture system for the laser and MWIR. Point spread function (PSF) ellipticity was introduced to evaluate the coupling efficiency of the laser receiving system. A small aperture stop and narrow filter were set in the secondary image plane and an afocal light path of the laser system, respectively, and the stray light suppression ability of the small aperture stop was verified by modeling and simulation. With high-precision manufacturing technology by single point diamond turning (SPDT) and a high-efficiency dichroic coating, the laser/MWIR common aperture optical system with a 𝜑300 mm aluminum alloy mirror obtained images of buildings at a distance of 5 km with great quality. A civil aviation aircraft detection experiment was conducted. The results show that the common aperture system could detect and track long-distance civil aviation aircraft effectively, and the coverage was more than 450 km (signal-to-noise ratio = 6.3). It satisfied the application requirements for earlier warning and ranging of long-range targets in the area of aviation, aerospace and ground detection systems.

• 한국소프트웨어감정평가학회 논문지
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• 제16권2호
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• pp.163-172
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• 2020

최근 인공지능과 빅데이터, 자연어처리 기술을 포함한 4차 산업혁명 관련 기술이 발전하면서 개인이나 팀 단독의 연구 및 개발 작업 방식의 한계를 가져오고 있다. 이런 한계를 극복하기 위하여 자신의 기술을 공개하고 협업하는 오픈소스 소프트웨어 개발 방식이 활발해지고 있으며, 회사 내부에서도 유사 개발 방법을 적용하여 회사 구성원들의 참여를 독려하고 품질을 개선하는 노력을 진행하고 있다. 이런 경향을 반영하여 IT 기술을 주도하는 선도 회사들은 적극적으로 오픈소스와 이너소스로 대변되는 공개 개발방식에 대한 지원 정책들을 제시하고 있다. 본 논문에서는 최근 활발히 논의되고 있는 오픈소스 모델, 이너소스 모델 및 그와 유사한 DevOps 모델을 소개하고 각각의 특징 및 구성 요소를 비교하였다. 비교 결과를 바탕으로 어떤 특정 모델의 우수성을 주장하는 것보다는 고객의 요구사항을 만족하면서 질적 향상을 도모할 수 있도록 각 장점에 따라 개인 또는 소속 기관의 소프트웨어 개발정책을 수립할 수 있을 것으로 판단한다.

• Steel and Composite Structures
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• 제41권5호
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• pp.681-695
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• 2021

Many existing transmission or communication towers designed several decades ago have undergone nonreversible performance degradation, making it hardly meet the additional requirements from upgrades in wind load design codes and extra services of electricity and communication. Therefore, a new-type non-destructive reinforcement method was proposed to reduce the on-site operation of drilling and welding for improving the quality and efficiency of reinforcement. Six built-up steel angle members were tested under compression to examine the reinforcement performance. Subsequently, the cyclic loading test was conducted on a pair of steel angle tower sub-structures to investigate the reinforcement effect, and a simplified prediction method was finally established for calculating the buckling bearing capacity of those new-type retrofitted built-up steel angles. The results indicates that: no apparent difference exists in the initial stiffness for the built-up specimens compared to the unreinforced steel angles; retrofitting the steel angles by single-bolt clamps can guarantee a relatively reasonable reinforcement effect and is suggested for the reduced additional weight and higher construction efficiency; for the substructure test, the latticed substructure retrofitted by the proposed reinforcement method significantly improves the lateral stiffness, the non-deformability and energy dissipation capacity; moreover, an apparent pinching behavior exists in the hysteretic loops, and there is no obvious yield plateau in the skeleton curves; finally, the accuracy validation result indicates that the proposed theoretical model achieves a reasonable agreement with the test results. Accordingly, this study can provide valuable references for the design and application of the non-destructive upgrading project of steel angle towers.