• Journal of Korean Tunnelling and Underground Space Association
• /
• v.14 no.4
• /
• pp.375-395
• /
• 2012

According to the local highway tunnel ventilation guideline, ventilation capacity calculation should be performed at the speed ranging from 10 km/h to 80 km/h. This is so reasonable method considering uncongested and congested traffic conditions in urban tunnels. But recently due to low traffic volume and very low congestion frequency in rural highway tunnels, it seems to be an inadequate way to apply the guideline. Therefore the calculation should be performed separately for the free flow and congested traffic cases classified by the appropriate decision model. This paper aims at determining unnecessary running speed range for reasonable tunnel ventilation design, considering free flow and congested traffic conditions. Firstly, traffic volumes in highway tunnels were collected and if any, the causes of congestion were investigated. And with concept of 'margin speed'($u-u_m$), the decision model on traffic congestion was developed. Applicability of the decision model was also analyzed with case study. According to the results, when design speed is 100 km/h, with V/C less than 0.1, then the range of unnecessary speed in tunnel ventilation design is less than 40 km/h; for $V/C{\leqq}0.35$, $V/C{\leqq}0.6$ and $V/C{\leqq}0.75$, the unnecessary speed ranges are found to be ${\leqq}30$, ${\leqq}20$ and ${\leqq}10km/h$, respectively.

• Archives of design research
• /
• no.16
• /
• pp.17-25
• /
• 1996

, \l!ernatives in multi dimensional decision prohlems generally possess numerous attrihutes by which they can be describ('d and compared, The ('\';dllation factors include all attributes that have Ic\'(']s specified by quantitative and qualitativc objectil'l'S, Howev'('f since qualitative factors arc difficul! to quantify as num('ral estimates, these factors have tended to bl' ignored without regard for their importance to human contrnl. In this study, the author adapted :j ('va]uation methods with critrria which have qualitative and qualitative attributes: the Intuitive Evaluation ~1cthods the Accumulativc' Evaluation Model the Benchmarking Evaluation Methods, and studied the corrC'iation between them, The results show that Ill(' :j Mrthods have reciprocal relationships under reliability (r=O, (XX)]] In order to removl' obstacles of desi!;n ev'aluation ( lots of timl' l'llnsumption, constr;lints of placc" difficulties of hu!;!' data procc'ssin!;), it is necessary to be developed a new ('va]uation syst('rn which could prov'idc' effective rat in!; of desi!;n v'alm's 10 make value judw'rnents, , \l!ernatives in multi dimensional decision prohlems generally possess numerous attrihutes by which they can be describ('d and compared, The ('\';dllation factors include all attributes that have Ic\'(']s specified by quantitative and qualitativc objectil'l'S, Howev'('f since qualitative factors arc difficul! to quantify as num('ral estimates, these factors have tended to bl' ignored without regard for their importance to human contrnl. In this study, the author adapted :j ('va]uation methods with critrria which have qualitative and qualitative attributes: the Intuitive Evaluation ~1cthods the Accumulativc' Evaluation Model the Benchmarking Evaluation Methods, and studied the corrC'iation between them, The results show that Ill(' :j Mrthods have reciprocal relationships under reliability (r=O, (XX)]] In order to removl' obstacles of desi!;n ev'aluation ( lots of timl' l'llnsumption, constr;lints of placc" difficulties of hu!;!' data procc'ssin!;), it is necessary to be developed a new ('va]uation syst('rn which could prov'idc' effective rat in!; of desi!;n v'alm's 10 make value judw'rnents,alm's 10 make value judw'rnents,

• Journal of KIISE:Software and Applications
• /
• v.32 no.3
• /
• pp.163-172
• /
• 2005

Product Line Engineering (PLE) has been widely accepted as a representative software reuse methodology by using core assets. Product line architecture (PLA) is a key element of core assets. However, current research works on designing PLA do not provide sufficient and detailed guidelines of defining PLA and reflecting variability in the architecture. In this paper, we present a reference model of PLA and propose a process to design PLA with detailed instructions. Especially architectural variability is codified by describing decision model depending variation points and traced through PLA activities. The proposed process would make it feasible to apply PLE to practice areas.

• KIEE International Transactions on Electrophysics and Applications
• /
• v.5C no.1
• /
• pp.14-17
• /
• 2005

In this paper, an automated methodology for generating model parameters considering real manufacturing processes is presented with verified results. In addition, the outcomes of applications to the next generation of flash memory devices using the parameters calibrated from the process specification decision are analyzed. The test vehicle is replaced with a well-calibrated TCAD simulation. First, the calibration methodology is introduced and tested for a flash memory device. The calibration errors are less than 5% of a full chip operation, which is acceptable to designers. The results of the calibration are then used to predict the I-V curves and the model parameters of various transistors for the design of flash devices.

• The Transactions of the Korean Institute of Electrical Engineers C
• /
• v.51 no.1
• /
• pp.5-14
• /
• 2002

In this paper, we analyze inductive interference in conductive material around 345 kV power transmission line, and evaluate the effects of mitigation wires. Finite element method (FEM) is used to numerically compute induced eddy currents as well as magnetic fields around powder transmission lines. In the analysis model, geometries and electrical properties of various elements such as power transmission line, buried pipe lines, overhead ground wire, and conducting earth are taken into accounts. The calculation shows that mitigation wire reduces fairly good amount of eddy currents in buried pipe line. To find the optimum magnetic field shielding location of mitigation wire, we applied evolution strategy algorithm, a kind of stochastic approach, to the analysis model. Finally, it was shown that we can find more effective shielding effects with optimum location of one mitigation wire than with arbitrary location of multi-mitigation wires around the buried pipe lines.

• Journal of the Korean Institute of Telematics and Electronics C
• /
• v.35C no.12
• /
• pp.66-76
• /
• 1998

In this paper, we implement a buffer capable of handling short loops references to statistically lower the miss rate of variable-length instructions stored in the instruction buffer. MAU(Mark Appending Unit) takes the instructions as they are fetched from external memory, performs some initial decode operations and stores the results of the decode in the buffer for reducing multiple decodes when instructions are executed repeatedly such as in a loop. It includes a decision block of whether hit or not for effectively processing branch instructions Each module of the proposed architecture of processing variable-length instruction is described in VHDL structurally and behaviorally and whether it is working well or not is checked on V-System simulator of Model Technology Inc. We synthesized and simulated the architecture using an ASIC Synthesizer tool with 0.6$\mu\textrm{m}$ 5-Volt CMOS COMPASS library. Operation speed is up to 140MHz. The architecture includes about 17,000 gates.

• Journal of Information Technology Services
• /
• v.5 no.2
• /
• pp.155-168
• /
• 2006

Software product line is a software product or a set of software system, which has common functions. We can develop a specific software product, which satisfies requirements of a particular market segment and a mission in a specific domain by reusing the core asset such as the developed software architecture through the software product line. Software development methodology based on the software product line can develop a software more easily and fast by reusing the developed software core asset. Developed countries of software technology select software product line as a core field of software production technology, and support technology development. In case of USA, CMU/SEI(Carnegie Mellon University/Software Engineering Institute) developed product-line framework 4.0 together with the industry and the Department of Defense. Europe is supporting the development of product line technology through ITEA(IT for European Advancement) program. However, industries in our country understand the necessity of software production technology based on product line concept for the purpose of increasing productivity, it is not sufficient to invest for this technology development. In this paper, we aim to construct the common architecture of software product line for production of the software product line.

• Journal of Korean Society of Transportation
• /
• v.23 no.3 s.81
• /
• pp.95-108
• /
• 2005

The purpose of this study is to develop the ITS evaluation model using the Probabilistic Risk Analysis (PRA) methodology and to demonstrate the goodness-of-fit of the large ITS projects through the comparative analysis between DEA and PRA model. The results of this study are summarized below. First, the evaluation mode] using PRA with Monte-Carlo Simulation(MCS) and Latin-Hypercube Sampling(LHS) is developed and applied to one of ITS projects initiated by local government. The risk factors are categorized with cost, benefit and social-economic factors. Then, PDF(Probability Density Function) parameters of these factors are estimated. The log-normal distribution, beta distribution and triangular distribution are well fitted with the market and delivered price. The triangular and uniform distributions are valid in benefit data from the simulation analysis based on the several deployment scenarios. Second, the decision making rules for the risk analysis of projects for cost and economic feasibility study are suggested. The developed PRA model is applied for the Daejeon metropolitan ITS model deployment project to validate the model. The results of cost analysis shows that Deterministic Project Cost(DPC), Deterministic Total Project Cost(DTPC) is the biased percentile values of CDF produced by PRA model and this project need Contingency Budget(CB) because these values are turned out to be less than Target Value(TV;85% value), Also, this project has high risk of DTPC and DPC because the coefficient of variation(C.V) of DTPC and DPC are 4 and 15 which are less than that of DTPC(19-28) and DPC(22-107) in construction and transportation projects. The results of economic analysis shows that total system and subsystem of this project is in type II, which means the project is economically feasible with high risk. Third, the goodness-of-fit of PRA model is verified by comparing the differences of the results between PRA and DEA model. The difference of evaluation indices is up to 68% in maximum. Because of this, the deployment priority of ITS subsystems are changed in each mode1. In results. ITS evaluation model using PRA considering the project risk with the probability distribution is superior to DEA. It makes proper decision making and the risk factors estimated by PRA model can be controlled by risk management program suggested in this paper. Further research not only to build the database of deployment data but also to develop the methodologies estimating the ITS effects with PRA model is needed to broaden the usage of PRA model for the evaluation of ITS projects.

• Korean Chemical Engineering Research
• /
• v.62 no.3
• /
• pp.214-224
• /
• 2024

Valves play an essential role in a chemical plant such as regulating fluid flow and pressure. Therefore, optimal selection of the valve size and type is essential task. Valve size and type have been selected based on theoretical formulas about calculating valve sizing coefficient (Cv). However, this approach has limitations such as requiring expert knowledge and consuming substantial time and costs. Herein, this study developed a model for predicting valve sizes and types using machine learning. We developed models using four algorithms: ANN, Random Forest, XGBoost, and Catboost and model performances were evaluated using NRMSE & R² score for size prediction and F1 score for type prediction. Additionally, a case study was conducted to explore the impact of phases on valve selection, using four datasets: total fluids, liquids, gases, and steam. As a result of the study, for valve size prediction, total fluid, liquid, and gas dataset demonstrated the best performance with Catboost (Based on R², total: 0.99216, liquid: 0.98602, gas: 0.99300. Based on NRMSE, total: 0.04072, liquid: 0.04886, gas: 0.03619) and steam dataset showed the best performance with RandomForest (R²: 0.99028, NRMSE: 0.03493). For valve type prediction, Catboost outperformed all datasets with the highest F1 scores (total: 0.95766, liquids: 0.96264, gases: 0.95770, steam: 1.0000). In Engineering Procurement Construction industry, the proposed fluid-specific machine learning-based model is expected to guide the selection of suitable valves based on given process conditions and facilitate faster decision-making.

• The Korean Journal of Air & Space Law and Policy
• /
• v.34 no.1
• /
• pp.39-77
• /
• 2019

Crew members engaged in international air transportation provide work in many countries due to the nature of their work. According to the Private International Act, the place where the employee habitually carries out his/her work plays an important role in the determination of the governing law of the international labor contract (Article 28, Paragraph 2) and in the decision of international jurisdiction (Article 28, Paragraphs 3 and 4). The concept of the place where the employee habitually carries out his/her work was proposed by the EU to determine international jurisdiction and governing law. In international aviation law, the legislative purpose of the place where the employee habitually carries out his/her work is different from that of home base, which is a concept introduced for fatigue management of the crew in order to secure the aviation safety; thus the place where the employee habitually carries out his/her work and home base are not the same concept. In order to determine the place where the employee habitually carries out his/her work, following matters should be considered comprehensively; (i) where the crew starts and ends work, (ii) where the aircraft the crew is performing work on is primarily parked, (iii) where the crew is informed of the instructions and organizes his/her work activities, (iv) where the crew is obliged to reside according to the labor contract, (v) where there is an office provided by the employer and available to the crew, (vi) where the crew is obliged to be when he/she is ineligible for the work or subject to discipline. However, since all of the above items are the same as the location of the home base, it is reasonable to consider the home base as the most important factor when deciding on the place where the employee habitually carries out his/her work. In contrast, the state where the aircraft is registered (Article 17 of the Chicago Convention), should not be regarded as a place of where the employee habitually carries out his/her work. In this case, CJEU provided the first judging standard for the concept of the place where the employee engaged in international air transportation habitually carries out his/her work. It is the interpretation of the Brussels regulations which became a model -for the Korean Private International Act,- so it would be helpful to understand the concept of the place where the employee habitually carries out his/her work.