• Smart Structures and Systems
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• v.30 no.5
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• pp.545-556
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• 2022

Through the examination of literatures, electronic commerce is a subject which is accepted in enterprises to define e-commerce adoption, trends, and issues that are assisting and obstructing its efficacy. E-commerce offers numerous advantages to consumer satisfaction in any place and helps the company to get a competitive benefit over its competitors. The Internet has expanded the scope of business. Many business information is available by the global network that supports information gathering between organizations, businesses and their clients, while various divisions of a business is increasing at an exponential rate. Meanwhile, there are a few barriers to proper e-commerce usage and adoption, such as reliable internet connections, poor e-commerce supporting infrastructures, logistics systems presenting socio-regulatory and poor transportation barriers and demonstrating the significant improvement of e-commerce reliable and affordable Internet provisions, i.e., Internet cost, intensity, and reasonable level of e-readiness. The operational and strategic significance of information-based virtual value chains for all organizations cannot be emphasized. As a consequence, this study confirms worldwide market elements of e-commerce, such as its issues, benefits, relevance, scope, facilitators and projects prospective obstacles in a developing economy.

• Structural Engineering and Mechanics
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• v.89 no.3
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• pp.225-238
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• 2024

In this paper, a quasi-3D hyperbolic shear deformation theory for the bending responses of a functionally graded (FG) porous micro-beam is based on a modified couple stress theory requiring only one material length scale parameter that can capture the size influence. The model proposed accounts for both shear and normal deformation effects through an illustrative variation of all displacements across the thickness and satisfies the zero traction boundary conditions on the top and bottom surfaces of the micro-beam. The effective material properties of the functionally graded micro-beam are assumed to vary in the thickness direction and are estimated using the homogenization method of power law distribution, which is modified to approximate the porous material properties with even and uneven distributions of porosity phases. The equilibrium equations are obtained using the virtual work principle and solved using Navier's technique. The validity of the derived formulation is established by comparing it with the ones available in the literature. Numerical examples are presented to investigate the influences of the power law index, material length scale parameter, beam thickness, and shear and normal deformation effects on the mechanical characteristics of the FG micro-beam. The results demonstrate that the inclusion of the size effects increases the microbeams stiffness, which consequently leads to a reduction in deflections. In contrast, the shear and normal deformation effects are just the opposite.

• Journal of Integrative Natural Science
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• v.16 no.4
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• pp.123-131
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• 2023

Breast cancer continues to pose a substantial worldwide health challenge, thereby requiring the development of innovative strategies to discover new therapeutic interventions. Signal Transducer and Activator of Transcription 3 (STAT-3) has been identified as a significant factor in the development of several types of cancer, including breast cancer. This is primarily attributed to its diverse functions in promoting tumour formation and conferring resistance to therapeutic interventions. This study presents an in silico drug repositioning approach that focuses on identifying specific inhibitors of STAT-3 for the purpose of treating breast cancer. We initially examined the structural and functional attributes of STAT-3, thereby elucidating its crucial involvement in cellular signalling cascades. A comprehensive virtual screening was performed on a diverse collection of drugs that have been approved by the FDA from zinc15 database. Various computational techniques, including molecular docking, cross docking, and cDFT analysis, were utilised in order to prioritise potential candidates. This prioritisation was based on their predicted binding energies and outer molecular orbital reactivity. The findings of our study have unveiled a Dihydroergotamine and Paritaprevir that have been approved by the FDA and exhibit considerable promise as selective inhibitors of STAT-3. In conclusion, the utilisation of our in silico drug repositioning approach presents a prompt and economically efficient method for the identification of potential compounds that warrant subsequent experimental validation as selective STAT-3 inhibitors in the context of breast cancer. The present study highlights the considerable potential of employing computational strategies to expedite the drug discovery process. Moreover, it provides valuable insights into novel avenues for targeted therapeutic interventions in the context of breast cancer treatment.

• Korean Journal of Applied Biomechanics
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• v.12 no.2
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• pp.307-318
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• 2002

To provide a guideline for the development of a web-based sport biomechanics class in undergraduate program, thirty web sites, searched via search engines in May 2002, were analyzed intensively. In terms of requirement of log-in, only one site of 30 sites required user name and password. Seventeen(57%) sites provided the lecture note, which had various file formats such as 59% if PDF, 29% of HTML, and 12% of PPT. Fourteen(47%) sites provided the assignment and grade information on web. Eleven(37%) sites provided various resource and links which were related in sports biomechanics. Only four(13%) sites provided discussion or online digitizing or kinematic analysis program. Based on above results, a guideline for the development of a virtual classroom for college level sport biomechanics. A web-based sport biomechanics class should be developed with consideration of several functions as follows; homepage design, lecture note, measurement of class attendance, collaborative research system, and web-based data collection and analysis software for biomechanics laboratory.

• Journal of Advanced Navigation Technology
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• v.3 no.2
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• pp.108-119
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• 1999

In recent, there has been remarkable progress in the field of GPS applications. In a few years, an appreciable number of aircraft will adopt GPS as a landing guidance system because GPS is more economic, more reliable and more accurate than any other aviation systems. In this respect, we have performed several helicopter landing flight tests based on the real-time DGPS system made in SNUGL (Seoul National University GPS Laboratory). From the experimental results, we found several problems Which should be fixed to adopt DGPS as a aircraft landing guidance system. In this paper, we will introduce the problems found in tests and also suggest modifications to solve the problems. Our modifications can be classified into three parts. The first is about the attitude determination with single GPS antenna. The second deals with the cockpit display module. The display was devised to integrate the Instrument Landing System(ILS) with tunnel-the-sky using virtual reality. With the display, pilot can achieve more safe landings. The last part is the digital map. We inserted digital map into our system and put direction indicator on the map using position information from GPS. It is very useful for pilot to find airports even in bad weather. Using the newly designed DGPS landing system, we conducted flight test at Kimhae International Airport, Pusan, Korea. It was successful! Our system can also satisfy Category-I criterion for aircraft landing approach and determine attitude angle with a high level of reliability. It is supported by video materials.

• Information Systems Review
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• v.9 no.2
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• pp.41-66
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• 2007

The e-marketplace is a virtual marketplace where buyers and sellers meet in order to conduct transactions through the intermediation of market-makers. For the success of an e-marketplace, it is crucial for the market-maker to induce both buyers and sellers to make active transactions in it. However, their participation is frequently deterred by potential risk factors caused mainly by the inherent, structural complexity of the e-marketplace. Therefore, it is a critical challenge for the market-maker to identify and manage the transactional risk perceived by both the buyers and sellers. In this paper, we investigate the sources of buyers' and sellers' perceived risks and their mitigating factors in the e-marketplace. Specifically, we derive an analysis framework based on the economic theory of agency relationship. The framework includes four sources of the risks(perceived information asymmetry, fears of seller opportunism, fears of buyer opportunism, and concerns about market-maker's role incompleteness) and five mitigators of the risks(website informativeness, trust in market-maker, trust in seller, product diagnosticity, and social presence). Then, we empirically verify the framework through a case study on four successful e-marketplaces, and provide implications and strategies for the market-maker to effectively manage the transactional risks.

• Journal of Drive and Control
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• v.12 no.4
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• pp.60-70
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• 2015

A front-end loader (FEL) mounted on an agricultural tractor is one of the most commonly used implements for farm work. However, when the tractor carries material using the bucket attached to the FEL on a sloping ground, the materials can spill or roll back over the operator due to the tilted body, thereby requiring the bucket surface to remain level at a constant value regardless of varying slopes. In this study, an active system for controlling the angle of the FEL bucket on a tractor based on the real-time measurement of ground slopes was developed to enable the bucket to constantly remain level. A FEL simulator operated based on an electro hydraulic proportional valve (EHPV) was constructed in the laboratory to develop a proportional-integral-derivative (PID) controller forming a virtual electronic control unit (ECU) on the computer, which could automatically adjust the bucket angles depending on varying input angles while sending SAE-J1939 associated messages via CAN BUS to the EHPV. The different parameter values for the PID controller due to the gravity effect of the bucket were determined using a manual PID tuning method while assuming that the tractor travels on either an ascending slope or a descending slope. The developed PID control-based self-leveling system showed a mean of steady-state errors of within $1^{\circ}$ and a mean of delayed times of ~ 0.8s when the step input of $+20^{\circ}$ was given, implying that the developed system and control algorithm would be effective in maintaining the bucket angle at a certain value. Future studies include the improvement of the control algorithm to reduce such a time delay as well as the application of the developed algorithm to the FEL mounted on a tractor tested at a testing ground.

• Journal of Astronomy and Space Sciences
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• v.14 no.2
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• pp.275-285
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• 1997

We have investigated Pi 2 pulsations which were observed both on ground magnetometer array and by satellites. On November 9th in 1994, Pi 2 pulsations appeared globally on the 190/210 magnetometer chain and Hermanus station when two satellites(EXOS-D and ETS-VI) were located near the magnetic meridian of the 210 array. The local time of measurements covers from morning(LT=8.47hr) to afternoon(LT=20.3hr) and the bandwidth of peak frequency is found relatively small. The signals of the electric field are highly coherent with ground-based observations with the out of phase oscillations. However, the magnetic field measurement on the ETS-VI in the outer magnetosphere(L=6.60) shows no signature of Pi 2 pulsations over the same time interval and the correlation with any of the ground-based stations is found to be very weak, even through both satellites and magnetometer chain are located close to each other in local time. We suggest that this event may be a direct evidence of Pi 2 pulsations as virtual resonant modes which are localized in the plasmasphere(Lee 1996). The results show that the cavity mode oscillations can occur in the inner magnetosphere with less spectral noise compared to the outer magnetospheric case.

• Journal of Life Science
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• v.26 no.2
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• pp.253-258
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• 2016

In this study, nano-micelled curcumin was produced with natural sea salt with a view to comparing the in silico molecular binding affinity of pure curcumin compound to the active site of transthyretin. Using an optical light microscope and an electron microscope, it was found that the structure of the surface and the cross-section of nano-micelled curcumin was significantly different from natural sea salt. In particular, the crystal structure and nano-components in the nano-micelled curcumin were united, and the layer was more strongly stabilized than untreated salts. In the virtual 3D structure, in silico molecular docking study, the ligand binding affinity of nano-micelled curcumin to the transthyretin active site was found to be higher than that of pure curcumin. In addition, a nano-micelled curcumin formula interacted with more amino acid residues of transthyretin domains. The pharmacophore feature of the nano-micelled curcumin also showed more condensed and constrained features than normal curcumin. These results suggest that nano-micelled curcumin may effectively bind to and stabilize transthyretin, thereby regulating transthyretin-related physiological diseases. Collectively, the nano-micelled curcumin process suggests that normal curcumin can be modified more efficiently into the novel bio-functional chemical formula to stabilize the transthyretin structure. Therefore, the nano-micelled curcumin process can be applied to the field of the regulation of Alzheimer's disease.

• Journal of the Korean Academy of Esthetic Dentistry
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• v.27 no.2
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• pp.82-96
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• 2018

3D printing is a process of producing 3d object from a digital file in STL format by joining, bonding, sintering or polymerizing small volume elements by layer. The various type of 3d printing is classified according to the additive manufacturing strategies. Among the types of 3D printer, SLA(StereoLithography Apparatus) and DLP(Digital Light Processing) 3D printer which use polymerization by light source are widely used in dental office. In the previous study, a full-arch scale 3d printed model is less precise than a conventional stone model. However, in scale of quadrant arch, a 3d printed model is significantly precise than a five-axis milled model. Using $3^{rd}$ Party dental CAD program, full denture, provisional crowns and diagnostic wax-up model are fabricated by 3d printer in dental office. In Orthodontics, based on virtual setup model, indirect bracket bonding tray can be generated by 3d printer. And thermoforming clear aligner can be fabricated on the 3d printed model. 3D printed individual drilling guide enable the clinician to place the dental implant on the proper position. The development of layer additive technology enhance the quality of 3d printing object and shorten the operating time of 3D printing. In the near future, traditional dental laboratory process such as casting, denture curing will be replaced by digital 3D printing.