• International Journal of Computer Science & Network Security
• /
• v.23 no.10
• /
• pp.188-198
• /
• 2023

In this era of globalization without limitation, many security issues occur, especially in a public network. Internet users significantly increased every single day. However, only some users are aware of security issues when they use Internet services. For the campus network environment, both staffs and students are susceptible to security threats such as data theft, unauthorized access and more due to different levels of awareness towards security threats. This paper is to study the level of awareness among students on security issues based on KSA model. As a case study, the survey was distributed among students in the UTeM campus network. A quantitative study was conducted, and a structured questionnaire has been designed and distributed among students. The variables were focused on three (3) aspects, which are Knowledge, Skill and Ability (KSA). The finding shows the relationship between KSA with the level of awareness among students has been revealed. From the result, Knowledge is the most significant aspect that contributes to high awareness. For the future, a study about increasing students' knowledge about security issues should be addressed.

• Steel and Composite Structures
• /
• v.49 no.3
• /
• pp.293-306
• /
• 2023

This article focuses on the study of the buckling behavior of two-dimensional functionally graded (2D-FG) nanosize tubes, including porosity, based on the first shear deformation and higher-order theory of the tube. The nano-scale tube is simulated using the nonlocal gradient strain theory, and the general equations and boundary conditions are derived using Hamilton's principle for the Zhang-Fu's tube model (as a higher-order theory) and Timoshenko beam theory. Finally, the derived equations are solved using a numerical method for both simply-supported and clamped boundary conditions. A parametric study is performed to investigate the effects of different parameters, such as axial and radial FG power indices, porosity parameter, and nonlocal gradient strain parameters, on the buckling behavior of the bi-dimensional functionally graded porous tube. Keywords: Nonlocal strain gradient theory; buckling; Zhang-Fu's tube model; Timoshenko theory; Two-dimensional functionally graded materials; Nanotubes; Higher-order theory.

• Steel and Composite Structures
• /
• v.36 no.2
• /
• pp.213-228
• /
• 2020

Shape Memory Alloys (SMAs) are new materials used in various fields of science and engineering, one of which is civil engineering. Owing to their distinguished capabilities such as super elasticity, energy dissipation, and tolerating cyclic deformations, these materials have been of interest to engineers. On the other hand, the connections of a steel structure are of paramount importance because of their vulnerabilities during an earthquake. Therefore, it is indispensable to find approaches to augment the efficiency and safety of the connection. This research investigates the behavior of steel connections with extended end plates equipped hybridly with 8 rows of high strength bolts as well as Nitinol superelastic SMA bolts. The connections are studied using component method in dual form. In this method, the components affecting the connections behavior, such as beam flange, beam web, column web, extended end plate, and bolts are considered as parallel and series springs according to the Euro-Code3. Then, the nonlinear force- displacement response of the connection is presented in the form of moment-rotation curve. The results obtained from this survey demonstrate that the connection has ductility, in addition to its high strength, due to high ductility of SMA bolts.

• The Korea Journal of Herbology
• /
• v.27 no.4
• /
• pp.73-80
• /
• 2012

Objectives : Under normal condition melanin protects the skin from extracellular stimuli including ultraviolet (UV)-induced oxidative skin damages, but excess production and accumulation of melanin can induce hyperpigmentation causing esthetic problems. Therefore, in this study we tried to search for natural skin whitening materials from marine natural resources. Methods : Water and ethanol extracts of marine natural resources were prepared from Porphyra thalli (PT), Laminariae thallus (LT), Ostreae concha (OC), Sargassum thallus (ST), Undaria thallus (UT), Codium thalli (CT), Enteromorpha thalli (ET), Syngnathoides biaculeatus (SB), and Hippocampus coronatus (Hc). Their effects against UVB and ${\alpha}$-melanocyte stimulating hormone (${\alpha}$-MSH)-induced melanogenesis were investigated based on melanin formation in B16 mouse melanoma cells. The mRNA and protein expression of enzymes involved in the melanogenic process were further examined by reverse transcriptase-polymerase chain reaction (RT-PCR) and Western blot analysis, respectively. Results : Water extract of Ostreae concha (OCW/E) effectively inhibited UVB and ${\alpha}$-MSH-induced melanin production in B16 melanocytes, which seemed to be mediated by inhibition of mRNA expression of tyrosinase and tyrosinase-related protein 1 (TRP-1). In another experiment, ethanol extracts from Porphyra thalli (PTE/E), Laminariae thallus (LTE/E), Sargassum thallus (STE/E), Undaria thallus (UTE/E), Codium thalli (CTE/E), Syngnathoides biaculeatus (SBE/E), and Hippocampus coronatus (HcE/E) significantly suppressed UVB and ${\alpha}$-MSH-induced melanin formation. Furthermore, ethylacetate fraction isolated form LTE/E (LTE/EEt) decreased UVB and ${\alpha}$-MSH-elevated extracellular melanin levels via inhibition of tyrosinase protein expression. Conclutions : These results suggest that marine natural resources such as Porphyra thalli, Laminariae thallus, Ostreae concha, Sargassum thallus, Undaria thallus, Codium thalli, Syngnathoides biaculeatus and Hippocampus coronatus have anti-melanogenic effects, thereby exhibiting high potentials to be utilized as one of the ingredients for the development of new whitening functional cosmetics.

• BMB Reports
• /
• v.45 no.7
• /
• pp.396-401
• /
• 2012

Overnutrition is one of the major causes of non-alcoholic fatty liver disease (NAFLD). NAFLD is characterized by an accumulation of lipids (triglycerides) in hepatocytes and is often accompanied by high plasma levels of free fatty acids (FFA). In this study, we compared the energy metabolism in acute steatotic and non-steatotic primary mouse hepatocytes. Acute steatosis was induced by pre-incubation with high concentrations of oleate and palmitate. Labeling experiments were conducted using [$U-^{13}C_5$,$U-^{15}N_2$] glutamine. Metabolite concentrations and mass isotopomer distributions of intracellular metabolites were measured and applied for metabolic flux estimation using transient $^{13}C$ metabolic flux analysis. FFAs were efficiently taken up and almost completely incorporated into triglycerides (TAGs). In spite of high FFA uptake rates and the high synthesis rate of TAGs, central energy metabolism was not significantly changed in acute steatotic cells. Fatty acid ${\beta}$-oxidation does not significantly contribute to the detoxification of FFAs under the applied conditions.

• Smart Structures and Systems
• /
• v.26 no.4
• /
• pp.403-418
• /
• 2020

In recent years, the use of Fiber Reinforced Polymers (FRPs) as one of the most common ways to increase the strength of concrete samples, has been introduced. Evaluation of the final strength of these specimens is performed with different experimental methods. In this research, due to the variety of models, the low accuracy and impact of different parameters, the use of new intelligence methods is considered. Therefore, using artificial intelligent-based models, a new solution for evaluating the bond strength of FRP is presented in this paper. 150 experimental samples were collected from previous studies, and then two new hybrid models of Imperialist Competitive Algorithm (ICA)-Artificial Neural Network (ANN) and Artificial Bee Colony (ABC)-ANN were developed. These models were evaluated using different performance indices and then, a comparison was made between the developed models. The results showed that the ICA-ANN model's ability to predict the bond strength of FRP is higher than the ABC-ANN model. Finally, to demonstrate the capabilities of this new model, a comparison was made between the five experimental models and the results were presented for all data. This comparison showed that the new model could offer better performance. It is concluded that the proposed hybrid models can be utilized in the field of this study as a suitable substitute for empirical models.

• Korean Journal of Food Science and Technology
• /
• v.30 no.3
• /
• pp.498-501
• /
• 1998

It was determined whether photostimulated luminescence (PSL) is applicable to the detection of post-irradiation of foods by measuring PSL photon counts for unirradiated and irradiated pepper powder, dried herbs, fresh shrimp, potato, soybean, dried fig, chestnut, dried squid, and dried cod. The samples were irradiated with $^{60}Co\;{\gamma}-ray$ source and PSL photon counts were measured for them. The photon counts of unirradiated samples were lower than 2,000 for potatoes and less than 1,000 for the others. The photon counts of the irradiated samples except dried figs (0.5 kGy), chestnuts (0.2 kGy), and dried squid (0.5 kGy) were higher than 1,000, and the photon counts increased with dose. Thus, PSL might be applied to the primary detection of irradiated foods.

• Steel and Composite Structures
• /
• v.31 no.6
• /
• pp.629-640
• /
• 2019

The investigation of retaining wall structures behavior under dynamic loads is considered as one of important parts for designing such structures. Generally, the performance of these structures is under the influence of the environment conditions and their geometry. The aim of this research is to design retaining wall structures based on smart and optimal systems. The use of accuracy and speed to assess the structures under different conditions is one of the important parts sought by designers. Therefore, optimal and smart systems are able to have better addressing these problems. Using numerical and coding methods, this research investigates the retaining wall structure design under different dynamic conditions. More than 9500 models were constructed and considered for modelling design. These designs include height and thickness of the wall, soil density, rock density, soil friction angle, and peak ground acceleration (PGA) variables. Accordingly, a neural network system was developed to establish an appropriate relationship between data to obtain safety factor (SF) of retaining walls under different seismic conditions. Different parameters were analyzed and the effect of each parameter was assessed separately. According to these analyses, the structure optimization was performed to increase the SF values. The optimal and smart design showed that under different PGA conditions, the structure performance can be appropriately improved while utilization of the initial (or basic) parameters leads to the structure failure. Therefore, by increasing accuracy and speed, smart methods could improve the retaining structure performance in controlling the wall failure. The intelligent design process of this study can be applied to some other civil engineering applications such as slope stability.

• Advances in concrete construction
• /
• v.16 no.6
• /
• pp.291-302
• /
• 2023

As the first part of the body that strikes the ground during running, sports shoes are especially important for improving performance and reducing injuries. The use of new nanotechnology materials in the shoe's sole that can affect the movement angle of the foot and the ground reaction forces during running has not been reported yet. It is important to consider the material of the sole of the shoe since it determines the long-term performance of sports shoes, including their comfort while walking, running, and jumping. Running performance can be improved by polymer foam that provides good support with low energy dissipation (low energy dissipation). Running shoes have a midsole made of ethylene propylene copolymer (EPP) foam. The mechanical properties of EPP foam are, however, low. To improve the mechanical performance of EPP, conventional mineral fillers are commonly used, but these fillers sacrifice energy return. In this study, to improve the magnificence of physical education training with nanotechnology, carbon nanotubes (CNTs) derived from recycled plastics were prepared by catalytic chemical vapor deposition and used as nucleating and reinforcing agents. As a result of the results, the physical, mechanical, and dynamic response properties of EPP foam combined with CNT and zinc oxide nanoparticles were significantly improved. When CNT was added to the nanocomposites with a weight percentage of less than 0.5 wt%, the wear resistance, physical properties, dynamic stiffness, compressive strength, and rebound properties of EPP foams were significantly improved.

• The Korean Journal of Nuclear Medicine Technology
• /
• v.18 no.1
• /
• pp.26-32
• /
• 2014

Purpose: As PET-MRI which has excellent soft tissue contrast is developed as integration system, many researches about clinical application are being conducted by comparing with existing display equipments. Because PET-MRI is actively used for head and neck cancer diagnosis in our hospital, lymph node metastasis before the patient's surgery was diagnosed and clinical usefulness of head and neck cancer PET-MRI scan was evaluated using pathological opinions and idiopathy surrounding tissue metastasis evaluation method. Materials and Methods: Targeting 100 head and neck cancer patients in SNUH from January to August in 2013. $^{18}F-FDG$ (5.18 MBq/kg) was intravenous injected and after 60 min of rest, torso (body TIM coil, Vibe-Dixon) and dedication (head-neck TIM coil, UTE, Dotarem injection) scans were conducted using $Bio-graph^{TM}$ mMR 3T (SIEMENS, Munich). Data were reorganized using iterative reconstruction and lymph node metastasis was read with Syngo.Via workstation. Subsequently, pathological observations and diagnosis before-and-after surgery were examined with integrated medical information system (EMR, best-care) in SNUH. Patient's diagnostic information was entered in each category of $2{\times}2$ decision matrix and was classified into true positive (TP), true negative (TN), false positive (FP) and false negative (FN). Based on these classified test results, sensitivity, specificity, accuracy, false negative and false positive rate were calculated. Results: In PET-MRI scan results of head and neck cancer patients, positive and negative cases of lymph node metastasis were 49 and 51 cases respectively and positive and negative lymph node metastasis through before-and-after surgery pathological results were 46 and 54 cases respectively. In both tests, TP which received positive lymph node metastasis were analyzed as 34 cases, FP which received positive lymph node metastasis in PET-MRI scan but received negative lymph node metastasis in pathological test were 4 cases, FN which received negative lymph node metastasis but received positive lymph node metastasis in pathological test was 1 case, and TN which received negative lymph node metastasis in both two tests were 50 cases. Based on these data, sensitivity in PET-MRI scan of head and neck cancer patient was identified to be 97.8%, specificity was 92.5%, accuracy was 95%, FN rate was 2.1% and FP rate was 7.00% respectively. Conclusion: PET-MRI which can apply the acquired functional information using high tissue contrast and various sequences was considered to be useful in determining the weapons before-and-after surgery in head and neck cancer diagnosis or in the evaluation of recurrence and remote detection of metastasis and uncertain idiopathy cervical lymph node metastasis. Additionally, clinical usefulness of PET-MRI through pathological test and integrated diagnosis and follow-up scan was considered to be sufficient as a standard diagnosis scan of head and neck cancer, and additional researches about the development of optimum MR sequence and clinical application are required.