• International Journal of Computer Science & Network Security
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• 제23권4호
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• pp.69-78
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• 2023

With the global rise of digital data, the uncontrolled quantity of data is susceptible to cyber warfare or cyber attacks. Therefore, it is necessary to improve cyber security systems. This research studies the behavior of malicious acts and uses Higuchi Fractal Dimension (HFD), which is a non-linear mathematical method to examine the intricacy of the behavior of these malicious acts and anomalies within the cyber physical system. The HFD algorithm was tested successfully using synthetic time series network data and validated on real-time network data, producing accurate results. It was found that the highest fractal dimension value was computed from the DoS attack time series data. Furthermore, the difference in the HFD values between the DoS attack data and the normal traffic data was the highest. The malicious network data and the non-malicious network data were successfully classified using the Receiver Operating Characteristics (ROC) method in conjunction with a scaling stationary index that helps to boost the ROC technique in classifying normal and malicious traffic. Hence, the suggested methodology may be utilized to rapidly detect the existence of abnormalities in traffic with the aim of further using other methods of cyber-attack detection.

• Asian Journal of Business Environment
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• 제12권1호
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• pp.25-33
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• 2022

Purpose: The purpose of this paper is to determine the effects of the Real Estate Transactions Tax (RETT) on the economic cycles of Saudi Arabia. A secondary purpose is to determine the effects of RETT on the construction and real estate sectors of Saudi Arabia. Research design, data and methodology: The data used is retrieved from the General Authority of Statistics, Saudi Central Bank and the World Bank Open Data. Econometric models of multiple linear regression with dummy variables have been conducted to achieve the objectives and to quantitatively verify the hypotheses. Results: With the VAT exemption in real estate transactions and its substitution with RETT, a positive effect on the economy and the real estate sector has been observed. However, this tax reform has not produced any significant effects in the construction sector. Conclusions: The main conclusion of the present research is that the real estate market has a major influence on economic cycles. After the tax reform, a reduction in the contribution of taxes on real estate transactions to GDP was detected. For the construction sector, after the tax reform, it is estimated that there will be an insignificant reduction in the contribution of the real estate price index, and of the taxes on real estate transactions, to GDP.

• Advances in nano research
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• 제14권5호
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• pp.443-450
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• 2023

Carbon nanotubes (CNTs) have received increased interest in reinforcing research for polymer matrix composites due to their exceptional mechanical characteristics. Its high surface area/volume ratio and aspect ratio enable polymer-based composites to make the most of its features. This study focuses on the experimental tensile testing and fabrication of carbon nanotube reinforced composite (CNTRC) beams, exploring various micromechanical models. By examining the performance of these models alongside experimental results, the research aims to better understand and optimize the mechanical properties of CNTRC materials. Tensile properties of neat epoxy and 0.3%; 0.4% and 0.5% by CNT reinforced laminated single layer (0°/90°) carbon fiber composite beams were investigated. The composite plates were produced in accordance with ASTM D7264 standard. The tensile test was performed in order to see the mechanical properties of the composite beams. The results showed that the optimum amount of CNT was 0.3% based on the tensile capacity. The capacity was significantly reduced when 0.4% CNT was utilized. Moreover, the experimental results are compared with Finite Element Models using ABAQUS. Hashin Failure Criteria was utilized to predict the tensile capacity. Good conformance was observed between experimental and numerical models. More importantly is that Young' Moduli of the specimens is compared with the prediction Halpin-Tsai and Mixture-Rule. Although Halpin-Tsai can accurately predict the Young's Moduli of the specimens, the accuracy of Mixture-Rule was significantly low.

• Nutrition Research and Practice
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• 제10권4호
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• pp.411-417
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• 2016

BACKGROUND/OBJECTIVES: Metabolic syndrome (MetS) is a set of interrelated metabolic risk factors that increase the risk of cardiovascular morbidity and mortality. Studies regarding the specificity and sensitivity of serum levels of leptin and uric acid as predictors of MetS are limited. The aim of this study was to evaluate the serum levels of leptin and uric acid in terms of their specificity and sensitivity as predictors of MetS in the studied Jordanian group. SUBJECTS/METHODS: In this cross sectional study, 630 adult subjects (308 men and 322 women) were recruited from the King Hussein Medical Center (Amman, Jordan). The diagnosis of MetS was made according to the 2005 International Diabetes Federation criteria. Receiver operating characteristic curves were used to determine the efficacy of serum levels of leptin and uric acid as predictors of MetS in the studied Jordanian group. RESULTS: Study results showed that for identification of subjects with MetS risk, area under the curve (AUC) for leptin was 0.721 and 0.683 in men and women, respectively. Serum uric acid levels in men showed no significant association with any MetS risk factors and no significant AUC, while uric acid AUC was 0.706 in women. CONCLUSION: Serum leptin levels can be useful biomarkers for evaluation of the risk of MetS independent of baseline obesity in both men and women. On the other hand, serum uric acid levels predicted the risk of MetS only in women.

• 한국미생물·생명공학회지
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• 제16권5호
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• pp.363-368
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• 1988

반합성 베타 락탐 항생물질의 가수분해 및 합성을 촉매하는 효소인 $\alpha$-acylamino-$\beta$-lactam acylhydrolase(ALAH)의 유전자를 Acetobacfer turbidans로부터 클론화하기 위한 연구를 수행하였다. 우선 순수 분리 정제된 효소에 대한 항혈청 (폴리클론 항체)을 제조한 다음 이를 probe로 하여 면역화학적 방법으로 유전자의 선별을 시도하였다. 이러한 용도로 개발된 운반체인 λ gtll에다 A. turbidans의 유전자 단편들을 삽입하여 genomic library를 제조한 후 이 library에서 유전자를 선별한 결과 두개의 positive clone을 얻을 수 있었다. 그러나. 이 두 clone들은 면역화학적으로 서로 다른 반응을 나타내었는데, 그 중 하나는 효소의 항혈청과는 잘 결합하나 융합되어진 베타 갈락토시다아제에 대한 항체와는 잘 결합하지 못하였고(λ gtll dn1), 또 다른 clone 은 이와 반대의 양상을 보여주었다(λ gtll dn2). 더구나 이들 clone을 여러 제한효소들로 분석해본 결과, 유전자가 삽입된 부분인 Eco RI 부위중 하나가 없어진 것을 알 수 있었다. 따라서 A. turbidans의 효소에 대한 유전자가 λ gtll에 클론화 되었으나 이 유전자와 베타 갈락토시다아제의 유전자(lacZ)간에 염기배열상 동위성이 있은 부위가 존재하여 재조합된 λ gtll 파지의 복제과정에서 삭제되어진 것으로 간주되어진다.

• 한국광학회지
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• 제1권1호
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• pp.22-27
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• 1990

결합형 모드록킹 극초단 색소레이저의 공진기 길이변화에 따른 펄스폭의 변화를 선형 자체상관기를 이용하여 연구하였다. 색소레이저의 공진기 길이가 여기레이저의 공진기 길이와 일치하였을 경우 펄스폭은 0.64ps이며 완벽하게 모드록킹 되었다. 그러나 최적조건보다 색소레이저 공진기 길이가 긴 경우나 짧은 경우에는 펄스폭은 넓어지며 불완전 모드록킹이 되었다. 즉 색소레이저의 공진기 길이가 여기레이저의 공진기 길이보다 길 경우는 자연방출에 의한 noise 때문에 broad base 가 형성되며, 색소 이득이 증가되기 때문에 자체 상관함수의 첨두출력은 최적조건에서의 색소레이저 공진기 길이보다 5 $\mu\textrm{m}$ 긴 조건에서 최대가 되었다. 또 색소레이저의 스펙트럼은 자연방출에 의한 형광 및 색소 이득이 증가되기 때문에 넓게 됨을 관찰할 수 있었다. 그러나 색소레이저의 공진기 길이가 여기 레이저의 공진기 길이보다 짧은 경우에는, 색소 이득이 적게 됨으로 자체 상관함수의 첨두출력도 약하게 되며 스펙트럼의 전반치폭은 좁게 되었다. 한편 최적조건을 벗어나면 스펙트럼의 중심파장이 이동되는 현상을 관찰할 수 있었다.

• International Journal of Computer Science & Network Security
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• 제21권8호
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• pp.229-237
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• 2021

Cloud of things (CoTs) is a newer idea which combines cloud computing (CC) with the Internet of Things (IoT). IoT capable of comprehensively producing data, and cloud computing can be presented pathways that allow for the progression towards specific destinations. Integrating these technologies leads to the formation of a separate element referred to as the Cloud of Things (CoTs). It helps implement ideas that make businesses more efficient. This technology is useful for monitoring a device or a machine and managing or connecting them. Since there are a substantial amount of machines that can run the IoT, there is now more data available from the IoT that would have to be stored on a local basis for a provisional period, and this is impossible. CoTs is used to help manage and analyze data to additionally create usable information by permitting and applying the development of advanced technology. However, combining these elements has a few drawbacks in terms of how secure the process is. This investigation aims to recent study literature from the past 3 years that talk about how secure the technology is in terms of protecting by authentication, reliability, availability, confidentiality, and access control. Additionally, this investigation includes a discussion regarding some kinds of potential attacks when using Cloud of Things. It will also cover what the various authors recommend and conclude with as well as how the situation can be approached to prevent an attack.

• Nuclear Engineering and Technology
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• 제53권1호
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• pp.282-293
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• 2021

This paper examines gamma-ray shielding properties of SBC-Bx glass system with the chemical composition of 40SiO₂-10B₂O₃-xBaO-(45-x)CaO- yZnO- zMgO (where x = 0, 10, 20, 30, and 35 mol% and y = z = 6 mol%). Mass attenuation coefficient (µ/ρ) which is an essential parameter to study gamma-ray shielding properties was obtained in the photon energy range of 0.015-15 MeV using PHITS Monte Carlo code for the proposed glasses. The obtained results were compared with those calculated by WinXCOM program. Both the values of PHITS code and WinXCOM program were observed in very good agreement. The (µ/ρ values were then used to derive mean free path (MFP), electron density (N_eff), effective atomic number (Z_eff), and half value layer (HVL) for all the glasses involved. Additionally, G-P method was employed to estimate exposure buildup factor (EBF) for each glass in the energy range of 0.015-15 MeV up to penetration depths of 40 mfp. The results reveal that gamma-ray shielding effectiveness of the SBC-Bx glasses evolves with increasing BaO content in the glass sample. Such that SBC-B35 glass has superior shielding capacity against gamma-rays among the studied glasses. Gamma-ray shielding properties of SBC-B35 glass were compared with different conventional shielding materials, commercial glasses, and newly developed HMO glasse. Therefore, the investigated glasses have potential uses in gamma shielding applications.

• International Journal of Computer Science & Network Security
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• 제21권2호
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• pp.66-76
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• 2021

The quality of the E-learning education in Saudi Arabia has been a major concern by many academicians, especially, and people in general as this platform has not been a priority for education. Not until recently, the world has been impacted by the Covid-19 pandemic, which makes every education institution shifted to the online platform to continue the education for the students. Thus, many studies on the perceptions on the online learning have been carried out, and though many are focusing on the perceptions by the education institutions' faculty and administration, there is a lack in the amount of study performed to analyse the students' perceptions of online learning during the pandemic time. The current study is conducted by utilising qualitative methods in order to collect information and investigate the students' perception regarding online learning during the pandemic Covid-19, based on their individual experiences. A number of fifteen (15) students were selected as respondents for the study, in which structured interviews were conducted by using a convenient sampling technique for data collection. Through the discussion, all of the positive and negative perceptions of online learning, as well as the factors contributing to those perceptions were identified. The results of the study found that the positive perceptions were contributed based on the flexibility, cost-effectiveness, availability of the electronic research databases, and well-designed online classroom interfaces. For the negative perceptions from using online learning platforms, the respondents informed that they were contributed by the lecturer's delayed feedback, lack of technical support by lecturers, low in self-esteem and self-motivation, feel isolated, one-way of educational methods, and poorly-designed class materials. Through the findings, the school's administration and lecturers would be able to know the struggles experienced by the students, and eventually come out with better solutions to improve their teaching methods.

• International Journal of Computer Science & Network Security
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• 제21권6호
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• pp.156-160
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• 2021

Every day brings a new challenge to the humanities. Life nowadays needs accuracy, privacy, integrity, authenticity, and security to run life systems especially the monetary system. Things now differ from previous centuries. Multiple varieties in digital banking have opened the new and most advanced innovations for human beings. The monetary system is going to developed day by day to facilitate the public. Electronic money has amazed the world and gave a challenge to central banking. For this purpose, there will be a need for strict security, information, and confidence. Blockchain technology has opened new gateways. Bitcoin has become the most famous digital currency, which has created a thunderstorm in digital marketing. Blockchain, as a new Financial Technology, has satisfied all the security issues and satisfied doing business in secure ways that encourage investors to invest and keep the world business wheel. Assessment of the sustainability of implementing Bitcoin in financial institutions will be discussed. Every new system has its pros and cons in which a clear vision of what we are about to use can be sought. Through this research paper, a demonstration of the monetary system evolution, the new ways of doing business, some evidence in a form of academic cases will be demonstrated through comparison a table, a suggested method to transfer to the new system in safe mode will be proposed, and a conclusion will be concluded.