• Fire Science and Engineering
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• v.15 no.3
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• pp.44-48
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• 2001

In this study, we analyzed the $CH_4$and $C_4$$H_{10}$ sensitivity measurement and voltage variation using catalytic type gas sensor characteristics in catalytic combustion type gas detecter sensors. Gas detector shall operate as intended when exposed for 24 hours to air having a relative humidity of 65 percent at a temperature of $20^{\circ}c$ and humidity of 85 percent at a temperature of $40^{\circ}c$. The gas detecter sensors are to be subjected to operation for 210 days in an area that has been determined to be equivalent to a typical residential atmosphere with an air velocity of 50 cm/sec. The source of energy for a gas detector sensors employing a supplementary basic circuit is energized from a seperate source of supply direct applied voltage 2.1V, 2.2V, 2.3V. As a result, it was confirmed that the relative humidity and temperature by regression each analysis, compared to the isobutane characteristic graph and methane characteristic graph by a relative humidity of 65% and 85% at a temperature($20^{\circ}c$, $40^{\circ}c$) show a similar linear pattern on the whore.

• Journal of KIISE:Computer Systems and Theory
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• v.27 no.2
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• pp.135-148
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• 2000

In this paper, we present a linear scheduling method for homogeneous multiprocessor systems using genetic algorithms. In general, genetic algorithms randomly generate initial strings, which leads to long operation time and slow convergence due to an inappropriate initialization. The proposed algorithm considers communication costs among processors and generates initial strings such that successive nodes are grouped into the same cluster. In the crossover and mutation operations, the algorithm maintains linearity in scheduling by associating a node with its immediate successor or predecessor. Linear scheduling can fully utilize the inherent parallelism of a given program and has been proven to be superior to nonlinear scheduling on a coarse grain DAG (directed acyclic graph). This paper emphasizes the usability of the genetic algorithm for real-time applications. Simulation results show that the proposed algorithm rapidly converges within 50 generations in most DAGs.

• Tunnel and Underground Space
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• v.28 no.4
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• pp.358-371
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• 2018

The stability of openings in the underground mine is major concern in the operation of mines that must ensure productivity and safety. Among many rock conditions affecting cavities stability, the width and height of the opening is an important design factor. In this paper, we consider to determine the maximum unsupported span of a opening in a limestone mine by using the Q system among several rock classification schemes. In order to determine the span of the unsupported opening in the limestone mine, rock mass classifications were carried out at over 200 sites in the underground limestone mines. The relationships by using the Q system and the stability graph proposed by Mathews to determine the maximum span of the unsupported opening were derived and compared. We propose a new classification method that combines GSI and RMR rock classification systems to make it easy to use in a field.

• Journal of the Korean Dietetic Association
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• v.12 no.4
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• pp.390-403
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• 2006

The purposes of this study were to : (a) examine the using pattern of college foodservice and off-campus restaurant and identify the important service quality attributes and levels for conjoint analysis, (b) investigate the demographic factor and the lunch behavior of "S" college's foodservice customer (c) search the optimum moving time to the college foodservice by cumulative graph, (d) identify the relative importance of the service quality attributes and level at college foodservice by conjoint analysis, and (e) provide the basic data for establishing new college foodservice. Questionnaire developed were conducted with 305 daytime students. A total of 284 were usable and the data was analyzed by the SPSS(ver. 11.0) for the descriptive analysis and conjoint analysis. ‘Low price’ was the reason for using college union foodservice, and the advantages of college union the foodservice were reported to be 'speediness', 'low price', 'near distance', 'wide space' and etc in a college. For off-campus restaurant, the using reasons were mentioned 'near distance', 'menu variety', 'kindness', and 'better taste and quality' and the using advantage found out 'inexpensive and enjoyable food with friends', and 'good taste'. An optimum time required for moving to the college foodservice was calculated 9 min by cumulative graph. As the relative important attributes on college foodservice were identified in the order of the ‘price range', the 'time required for the movement' and the 'food taste', and the level were analyzed the location requiring 6~10 minutes for the movement, the price range of 2,100~2,500 won, and the providing tasty foods by conjoint analysis. As "S" college will be established a new college foodsrevice suggested by the this study result, there should be expected the increasing salse and the college student's satisfaction on campus foodservice.

• Journal of KIISE:Databases
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• v.28 no.3
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• pp.418-429
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• 2001

Recently, a GIS has been applicable to the most important computer applications such as urban information systems and transportation information systems. These applications require spatial operations for an efficient management of a large volume of data. In particular, a spatial join among basic operations has the property that its response time is increased exponentially according to the number of spatial objects included in the operation. Therefore, it is not proper to the systems demanding the fast response time. To satisfy these requirements, the efficient parallel processing of spatial joins has been required. In this paper, the efficient method for creating and allocating tasks to balance statically the load of each processor in a parallel spatial join is presented. A task graph is developed in which a vertex weight is calculated by the cost model I have proposed. Then, it is partitioned through a graph partitioning algorithm. According to the experiments in CC16 parallel machine, our method made an improvement in the static load balance by decreasing the variance of a task execution time on each processor.

• The KIPS Transactions:PartD
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• v.8D no.6
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• pp.799-812
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• 2001

As XML become more popular for encoding data and exchanging format on the web, recent work on processing XML Document in DBMS has been performed. However, there is no formal data model for XML, and there is lack of research on XML algebra for processing complex XML query and even the mediators have many restrictions. Therefore, this paper proposes formal data model and algebra based on directed edge labeled graph for XML query. To implement algebra, not only algorithms of operation for algebra are presented, but also they are implemented using access method and path index based on RDBMS or ORDBMS. In particular, experiments to show the effectiveness of the implemented algebra are performed on XML documents on EST data which are semistructured data.

• Fire Science and Engineering
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• v.28 no.3
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• pp.72-79
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• 2014

The purpose of this study is to draw the improvement plan through the analysis of problems of main stretchers that are being used by the 119 EMS. In order to find out the problems, we used the literature review and analysis, survey questionnaire and we also made full use of KJ method (Kawakita Jiro method, affinity diagram), graph method, and priority matrix method to produce the improvement indicators. The problems of main stretchers are summarized as follows. they are being recognized as part of the emergency vehicle, they have the imperfection of performance verification criteria, and they cause the injuries of paramedics and patients accidents in operation. The indicators such as the ease of operation, the high performance, the multi-function, the driving performance, the durability and the lightweight, was produced to improve the problems. The results of the interconnection analysis and the applying priority matrix method on the indicators are the ease of operation ${\rightarrow}$ the multi-function ${\rightarrow}$ the driving performance ${\rightarrow}$ the high performance ${\rightarrow}$ the durability and the lightweight in order of importance.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.1C
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• pp.87-92
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• 2006

An $AB^2$ modular operation is an efficient basic operation for the public key cryptosystems and various systolic architectures for $AB^2$ modular operation have been proposed. However, these architectures have a shortcoming for cryptographic applications due to their high area complexity. Accordingly, this paper presents an partitioned $AB^2$ systolic modular multiplier over GF($2^m$). A dependency graph from the MSB $AB^2$ modular multiplication algorithm is partitioned into 1/3 to get an partitioned $AB^2$ systolic multiplier. The multiplier reduces the area complexity about 2/3 compared with the previous multiplier. The multiplier could be used as a basic building block to implement the modular exponentiation for the public key cryptosystems based on smartcard which has a restricted hardware requirements.

• 제어로봇시스템학회:학술대회논문집
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• 1991.10b
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• pp.1705-1711
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• 1991

On-line fault detection and diagnosis has an increasing interest in a chemical process industry, especially for a process control and automation. The chemical process needs an intelligent operation-aided workstation which can do such tasks as process monitoring, fault detection, fault diagnosis and action guidance in semiautomatic mode. These tasks can increase the performance of a process operation and give merits in economics, safety and reliability. Aiming these tasks, series of researches have been done in our lab. Main results from these researches are building appropriate knowledge representation models and a diagnosis mechanism for fault detection and diagnosis in a chemical process. The knowledge representation schemes developed in our previous research, the symptom tree model and the fault-consequence digraph, showed the effectiveness and the usefulness in a real-time application, of the process diagnosis, especially in large and complex plants. However in our previous approach, the diagnosis speed is its demerit in spite of its merits of high resolution, mainly due to using two knowledge models complementarily. In our current study, new knowledge representation scheme is developed which integrates the previous two knowledge models, the symptom tree and the fault-consequence digraph, into one. This new model is constructed using a material balance, energy balance, momentum balance and equipment constraints. Controller related constraints are included in this new model, which possesses merits of the two previous models. This new integrated model will be tested and verified by the real-time application in a BTX process or a crude unit process. The reliability and flexibility will be greatly enhanced compared to the previous model in spite of the low diagnosis speed. Nexpert Object for the expert system shell and SUN4 workstation for the hardware platform are used. TCP/IP for a communication protocol and interfacing to a dynamic simulator, SPEEDUP, for a dynamic data generation are being studied.

• Journal of the Korean Vacuum Society
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• v.20 no.1
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• pp.1-6
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• 2011

A sudden step change is observed in the vertical position readings from beam position monitors (BPMs) mounted at the several sector vacuum chambers of Pohang Light Source. To study the source of this sudden step change, we measured the RF transmission scattering matrix (S21) through the pickup electrodes of BPMs mounted at the both ends of the sector vacuum chamber. The measured $S_{21}$ graph of the sector vacuum chambers suffering sudden step change has a peak in the BPM operation frequency bandwidth. Otherwise that of the other sector vacuum chambers doesn't have a peak. It is shown by the numerical simulation that the peak found in the BPM operation frequency bandwidth corresponds to the longitudinal harmonic of transverse electric resonance mode.