• Journal of the Korean Mathematical Society
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• v.31 no.4
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• pp.539-544
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• 1994

We [1] investigated the Hausdorff dimension and the packing dimension of a certain perturbed Cantor set whose ratios are unformly bounded. In this paper, we consider a specific Cantor set whose ratios are not necessarily uniformly bounded but satisfy some other conditions. In fact, in the hypothesis, only the condition of the unform boundedness of ratios on the set is substituted by a "*-condition". We use energy theory related to Hausdorff dimension in this study while we [1] used Hausdorff density theorem to find the Hausdorff dimension of some perturbed Cantor set. In the end, we given an example which explains aformentioned facts.ned facts.

• Proceedings of the KSR Conference
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• 2010.06a
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• pp.2262-2269
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• 2010

A recent Tilting train development operation for existing line high speed, already developed "Korean Tilting Train eXpress(bellow TTX)" and that doing demonstration of operation. And TTX are going to commercial service in 2012. They are preparing Environmental Declaration of Product(bellow EDP) for offering environmental impact of TTX to customer. EDP calculated environmental impact of target product's whole life cycle(raw material and manufacturing, distribution, use, end of life) more quantity for that improving environmental impact and then certification them, it is using for that estimate some part of existence of specific pollutants, GHGs, energy consumption and recycling ratio. In this study, 1) analyze the process of getting EDP, 2) satisfy common criteria and each criteria(plan) in the Product Category Rules(bellow PCRs) provided KEITI, 3) according to ISO 14044, implementation of LCA. 4) These results be shown Characterized Impact(bellow CI) about each life cycle stage and six impact categories(ARD, GWP, OD, AD, EU, POC).

• 한국전산유체공학회:학술대회논문집
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• 1997.10a
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• pp.143-148
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• 1997

Differential pressure Venturi cone flowmeter is an advanced flowmeter which has many advantages such as wide range of measurement, high accuracy, excellent flow turndown ratio, low headless, and short installation pipe length requirement, etc. Like other differential pressure flowmeter, Venturi cone flowmeter uses the law of energy conservation, but its shape and position make it perform better than others. The cone acts as its own flow conditioner and mixer, fully conditioning and mixing the flow prior to measurement. For the analysis, we use Reynolds-averaged Navier-Stokes equations and $k-{\omega}$ turbulence model. The equations are fully trans-formed in the computational coordinates, the pressure-velocity coupling is made through SIMPLER algorithm, and the equations are discretized using analytic solutions of the linearized equations(Finite Analytic Method). At the end of the paper, using the result of analysis, We propose a new shape of cone with the hope of drag reduction and high performance.

• Food Science and Biotechnology
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• v.14 no.6
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• pp.758-765
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• 2005

Instant powders that only require mixing with water prior to consumption can be produced by extrusion for use in products such as instant beverages. Both extrusion processing conditions and particle size of powder are important to end-product characteristics. In this study, a twin-screw extruder was used under various processing conditions (feed moisture, barrel temperature, and screw speed) to produce extrudates from soft wheat flour, which were ground to powders with particle size ranges of less than 93, 93-145, and $145-249\;{\mu}m$. Effects of adding soy lecithin to wheat flour before extrusion were also investigated. Water absorption, solubility, suspension viscosity, and dispersibility of wheat powders were related to specific. mechanical energy measured during extrusion. Powder particle size was important to instant properties, especially ease of dispersal in water and stability to sedimentation. Addition of lecithin significantly improved dispersibility of powders.

• Nuclear Engineering and Technology
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• v.45 no.4
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• pp.459-468
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• 2013

During a station blackout (SBO), the initiating event is a loss of Class IV and Class III power, causing the loss of the pumps, used in systems such as the primary heat transporting system (PHTS), moderator cooling, shield cooling, steam generator feed water, and re-circulating cooling water. The reference case of the SBO case does not credit any of these active heat sinks, but only relies on the passive heat sinks, particularly the initial water inventories of the PHTS, moderator, steam generator secondary side, end shields, and reactor vault. The reference analysis is followed by a series of sensitivity cases assuming certain system availabilities, in order to assess their mitigating effects. This paper also establishes the strategies to mitigate SBO accidents. Current studies and strategies use the computer code of the Integrated Severe Accident Analysis Code (ISAAC) for Wolsong plants. The analysis results demonstrate that appropriate strategies to mitigate SBO accidents are established and, in addition, the symptoms of the SBO processes are understood.

• Smart Media Journal
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• v.13 no.1
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• pp.45-51
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• 2024

Long Range Wide Area Network (LoRaWAN) is a widely adopted Internet of Things (IoT) protocol due to its high range and lower energy consumption. LoRaWAN utilizes Adaptive Data Rate (ADR) for efficient resource (e.g., spreading factor and transmission power) management. The ADR manages these two resource parameters on the network server side and end device side. This paper focuses on analyzing the ADR and Gaussian ADR performance of LoRaWAN. We have performed NS3 simulation under a static scenario by varying the antenna height. The simulation results showed that antenna height has a significant impact on the packet delivery ratio. Higher antenna height (e.g., 50 m) has shown an improved packet success ratio when compared with lower antenna height (e.g., 10 m) in static and mobility scenarios. Based on the results, it is suggested to use the antenna at higher allevation for successful packet delivery.

• Journal of Industrial Technology
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• v.25 no.B
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• pp.81-87
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• 2005

This project addresses the product identification and design application of corrugated products for kinetic architectural applications. Initially, an architectural approach to product identification was carried out with the end goal of demonstrating application design principles of numerous novel architectural examples from the forest products industry. A design and prototyping stage followed demonstrating such application design principles and functional analysis on various novel architectural examples. The results of coupling product identification with proven application advantages will be of potential value not only to architecture but also to other designers in the arts and sciences. The general motivation for the research arises out of a growing interest corrugated and paper products to be ideally suited for various architectural applications for their unparallel environmental benefits. Applications in architecture that use fewer resources and that adapt efficiently to complex and changing conditions are particularly relevant for an industry (architecture) that is increasingly aware of its environmental responsibilities. Corrugated and paper products are highly under-utilized by the building industry as design choice material for both interior and exterior applications. An increased awareness of the benefits of corrugated and paper products coupled with a process of designing for the total use and reuse will prove to be a valuable means by which issues of energy efficiency and environmental quality of buildings could be enhanced to be more efficient, affordable, and therefore reach a broader audience of users.

• 한국연소학회:학술대회논문집
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• 2005.10a
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• pp.58-63
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• 2005

As fuel cells approach commercialization, hydrogen production becomes a critical step in the overall energy conversion pathway. Reforming is a process that produces a hydrogen-rich gas from hydrocarbon fuels. Hydrogen production via autothermal reforming (ATR) is particularly attractive for applications that demand a quick start-up and response time in a compact size. However, further research is required to optimize the performance of autothermal reformers and accurate models of reactor performance must be developed and validated. The design includes the requirement of accommodating a wide range of experimental set ups. Factors considered in the design of the reformer are capability to use multiple fuels, ability to vary stoichiometry, precise temperature and pressure control, implementation of enhancement methods, capability to implement variable catalyst positions and catalyst arrangement, ability to monitor and change reactant mixing, and proper implementation of data acquisition. A model of the system was first developed in order to calculate flowrates, heating, space velocity, and other important parameters needed to select the hardware that comprises the reformer. Predicted performance will be compared to actual data once the reformer construction is completed. This comparison will quantify the accuracy of the model and should point to areas where further model development is required. The end result will be a research tool that allows engineers to optimize hydrogen production via autothermal reformation.

• Nuclear Engineering and Technology
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• v.42 no.2
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• pp.145-150
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• 2010

The paper is describing work being developed in the frame of a 5-year IAEA Coordinated Research Programme (CRP) started in late 2005. Participants gained knowledge of modelling methodologies and experience in the development and use of rather sophisticated simulation tools in support of site characterization and performance assessment calculations. These goals were achieved by a coordinated effort, in which the advantages and limitations of numerical models are examined and demonstrated through a comparative analysis of simplified, illustrative test cases. This knowledge and experience should help them address these issues in their own country's nuclear waste program. Coordination efforts during the first three years of the project aimed at enabling this transfer of expertise and maximizing the learning experience of the participants as a group. This was accomplished by identifying common interests of the participants (i.e., Process Modelling and Total System Performance Assessment methodology), and by defining complementary tasks that are solved by the members. Synthesis of all available results by comparative assessments is planned in the coming months. The project will be completed end of 2010. This paper is summarizing activities up to November 2009.

• Journal of Mechanical Science and Technology
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• v.20 no.6
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• pp.864-873
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• 2006

As fuel cells approach commercialization, hydrogen production becomes a critical step in the overall energy conversion pathway. Reforming is a process that produces a hydrogen-rich gas from hydrocarbon fuels. Hydrogen production via autothermal reforming (ATR) is particularly attractive for applications that demand a quick start-up and response time in a compact size. However, further research is required to optimize the performance of autothermal reformers and accurate models of reactor performance must be developed and validated. The design includes the requirement of accommodating a wide range of experimental set ups. Factors considered in the design of the reformer are capability to use multiple fuels, ability to vary stoichiometry, precise temperature and pressure control, implementation of enhancement methods, capability to implement variable catalyst positions and catalyst arrangement, ability to monitor and change reactant mixing, and proper implementation of data acquisition. A model of the system was first developed in order to calculate flowrates, heating, space velocity, and other important parameters needed to select the hardware that comprises the reformer. Predicted performance will be compared to actual data once the reformer construction is completed. This comparison will quantify the accuracy of the model and should point to areas where further model development is required. The end result will be a research tool that allows engineers to optimize hydrogen production via autothermal reformation.