• Journal of Electrical Engineering and Technology
• /
• v.12 no.1
• /
• pp.486-493
• /
• 2017

Refineries and chemical plants with isolated power systems that have a limited power supply are more susceptible to voltage changes from disturbances compared to power systems connected with a power company. Furthermore, most loads in such cases are induction motor loads, and therefore, transient voltage characteristics when starting a high-capacity motor must be examined. In general, high-capacity motors are customized appropriately to the load performance curve by the manufacturer during the construction of an industrial plant. Subsequently, when complying with the voltage drop permitted by international standards during the design process, power supply equipment such as transformers and generators is overdesigned. Therefore, a novel analysis is necessary on standards for startup and constraint voltage drops, as well as on identifying the voltage drop limitations for starting high-capacity motors in refineries and chemical plants with isolated power systems. In this study, field tests on an industrial plant were conducted, and simulations modeled under conditions identical to those of the field test system were performed using the general-purpose program ETAP in order to compare the results.

• The Korean Journal of Ecology
• /
• v.21 no.4
• /
• pp.337-344
• /
• 1998

To select tolerant species among the Korean major woody plants for restoring disturbed ecosystems by air and soil pollution, we transplanted the seedlings of 56 species in control and polluted sites within Yeocheon industrial complex area, and compared their aboveground growth characteristics such as total branch length, total leaf weight, and maximum photozynthetic rate. Tolerant species growting better in polluted site than in control site was Quercus variabilis, Pinus thunbergii, Q. aliena, P. densiflora, Styrax japonica, Alnus firma, Celtis sinensis, Elaeagnus umbellata, Q. serrata, japonica, Sorbus alnifolia, and Q. acutissimia in local tree occuring within polluted area group (80%), Ailanthus altissima in street tree group (20%), Populus tomentiglandulosa and A. hirsuta var. sibirica in fast growing tree group (50%), Acer ginala and Abies holophylla in late successional tree group (20%), Betulla platyphylla var. japonica, Acer truncatum, A. palmatum, Syringa dilatata, and Rosa multifora in garden tree group (38%), and Q. rubura, and Robinia pseudoacacia in foreign restoring tree group (20%), respectively. The remaining plant species, 37 species (57% of total species), were classified into sensitive species to pollution. Those tolerant species can be utilized for restoration of the degraded ecosystem in this polluted area.

• Journal of Welding and Joining
• /
• v.17 no.6
• /
• pp.53-61
• /
• 1999

The use of thick plate in increasing in recent years due to the rapid expansion of chemical plants, nuclear plants, ships and other industrial plants. Welding is the most popular joining techniques employed in manufacturing industrial machineries and structures. Normally, Groove shapes are prepared according to appropriate rules and regulations such as KS, JIS, AWS, LR, DNV and etc. for various thicknesses of plate. However those groove angles tend to be too large. As a result of large groove angle, residual stress, deformation of material and strength reduction is obtained. Therefore, the reliability and safety of structures and machinery tend to be decreasing. Therefore, in this paper, theoretical as well as experimental study are carried out to find optimum groove shapes for T-welded joint of mild steel. The test specimen are made in same condition with simulation model. Welding residual stresses measurement by sectional cutting method. ⅰ) The mechanical difference for change the thickness of plate and groove angle are not appeared. ⅱ) In a mechanical point of view minimum preparation angle(40°) is more suitable than maximum groove angle(60℃). ⅲ) The measurement value and distribution of welding residual stresses are not effected largely by groove angle. It is mechanical restraint that mainly affect welding residual stresses distribution. In mechanical point of view minimum groove angle is more suitable than maximum groove angle. Therefore, it is appropriate to minimize the size of groove shape in strength and safety.

• Journal of the Korean Chemical Society
• /
• v.55 no.6
• /
• pp.1018-1023
• /
• 2011

Alzinc is a ursine situated in the Ghazaouet town western part of the republic of Algeria. The purpose of this study was to determine the degree of contamination which soil and plants are burdened with some heavy metals: Pb, Zn, Ni, Cu, Cd, Mn, Cr, Fe and As, then the accumulation of heavy metals in the soil and plant adjacent of area the alzinc ursine was detected and the interdependence of pollution among all three regions of the environment determined. This paper analyzes the heavy metal contents within a 2-years period in the soil and plants at the beginning of the vegetation period. The presence of Pb, Zn, Ni, Cu, Cd, Mn, Cr, Fe and As, in the samples were analyzed using Inductively Coupled Plasma-Atomic Emission Spectrometry (ICP-AES). Measurements of heavy metal contents were performed at three locations in soil and vegetative parts of three-plant types (plant alimentary) period during summer. The plant samples from the immediate environment of the dumpsite were highly contaminated with Zn, Cd and Mn. Three plants species: grape, artichoke and pepper, particularly, grape met some of the conditions to be classified as accumulators for Zn, Cu, Cd and Fe, consequently, she revealed a health risk for human and livestock due to the spread of the metal pollution from waste dumpsites to agricultural areas.

• Industrial Engineering and Management Systems
• /
• v.3 no.1
• /
• pp.52-58
• /
• 2004

This report examines the issue of designing an efficient production system by increasing several types of flexibility. Increasing manufacturing flexibility is a key strategy for efficiently improving market responsiveness in the face of uncertain market demand for final products. The manufacturing system comprises multiple plants, of which individual plants have multiple manufacturing lines that are designed to produce limited types of products in accordance with their size and materials. Imbalance in the workload occurs among plants as well as among manufacturing lines because of fluctuations in market demand for final products. Thereby, idleness of some manufacturing lines and longer lead times in some manufacturing lines occur as a result of the high workload. We clarify how these types of flexibility affect manufacturing performance by improving only one type of flexibility or by improving multiple types of flexibility simultaneously. The average lead time and the imbalance in workload are adopted as measures of manufacturing performance. Three types of manufacturing flexibility are interrelated: machine flexibility, routing flexibility, and process flexibility. Machine flexibility refers to the various types of operations that a machine can perform without requiring the prohibitive effort of switching from one order to another. Routing flexibility is the capability of processing a given set of part types using more than one line (alternative line) in the plant. Process flexibility results from being able to build different types of final products at the same plant.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.9 no.6
• /
• pp.1574-1580
• /
• 2008

In this paper, to bring under robust and accurate control of auto-equipment systems which disturbance, parameter alteration of system, uncertainty and so forth exist, neural network controller called dynamic neural processor(DNP) is designed In order to perform a elaborate task like as assembly, manufacturing and so forth of components, tracking control on the trajectory of power coming in contact with a target as well as tracking control on the movement course trajectory of end-effector is indispensable. Also, the learning architecture to compute inverse kinematic coordinates transformations in the Plants of auto-equipment systems is developed and the example that DNP can be used is explained. The architecture and learning algorithm of the proposed dynamic neural network, the DNP, are described and computer simulations are provided to demonstrate the effectiveness of the proposed learning method using the DNP.

• Nuclear Engineering and Technology
• /
• v.55 no.2
• /
• pp.603-622
• /
• 2023

Human error (HE) is an important concern in safety-critical systems such as nuclear power plants (NPPs). HE has played a role in many accidents and outage incidents in NPPs. Despite the increased automation in NPPs, HE remains unavoidable. Hence, the need for HE detection is as important as HE prevention efforts. In NPPs, HE is rather rare. Hence, anomaly detection, a widely used machine learning technique for detecting rare anomalous instances, can be repurposed to detect potential HE. In this study, we develop an unsupervised anomaly detection technique based on generative adversarial networks (GANs) to detect anomalies in manually collected surveillance data in NPPs. More specifically, our GAN is trained to detect mismatches between automatically recorded sensor data and manually collected surveillance data, and hence, identify anomalous instances that can be attributed to HE. We test our GAN on both a real-world dataset and an external dataset obtained from a testbed, and we benchmark our results against state-of-the-art unsupervised anomaly detection algorithms, including one-class support vector machine and isolation forest. Our results show that the proposed GAN provides improved anomaly detection performance. Our study is promising for the future development of artificial intelligence based HE detection systems.

• Korean Journal of Environment and Ecology
• /
• v.24 no.4
• /
• pp.363-394
• /
• 2010

This study was carried out to investigate the vascular flora of the Hongcheon-gun area in Gangwon Province. The vascular plants were collected 13 times(from April 2008 to May 2009), and 1,055 taxa in total were identified, including 43 orders, 118 families, 443 genera, 903 species, 6 subspecies, 125 varieties, 18 form and 3 hybrids. Among them, 37 taxa of Korean endemic plants and the Office of Forestry-designated rare & endangered plants were identified as 35 taxa. Based on the list of plants which have been approved for overseas delivery, 61 taxa were recorded in the investigated area. The Ministry of Environment-designated plants, which should be protected by the wildlife protection law, were identified as four taxa and 224 taxa of specially designated plants by the Ministry of Environment. The naturalized plants were identified as 45 taxa, and their naturalization ratio and urban index were found to be 4.3%, and 16.1% respectively. 1,055 taxa listed consists of 359 taxa(34%) of edible plants, 293 taxa(27.7%) of medicinal plants, 166 taxa(15.7%) of pasture plants, 143 taxa(13.5%) of ornamental plants, 41 taxa(3.9%) of timber plants, 25 taxa(2.3%) of fiber plants and 3 taxa(0.2%) of industrial plants.

• Korean Journal of Plant Resources
• /
• v.27 no.5
• /
• pp.477-484
• /
• 2014

This study was carried out to investigate the vascular plants of the Mt. Galjeongok-bong (1204 m) Protected Area for Forest Genetic Resource Conservation. The vascular plants collected 12 times (from March 2007 to October 2012) were consisted of total 385 taxa; 82 families, 232 genera, 335 species, 4 subspecies, 43 varieties and 3 forms respectively. Among them, 9 taxa Korean endemic plants and 21 taxa of Korean rare plants were investigated in addition to 89 taxa of specially designated plants announced by the Ministry of Environment. The naturalized plants were 9 taxa, therefore naturalized ratio was 2.3%. 385 taxa listed consists of 152 taxa (39.5%) of edible plants, 123 taxa (31.9%) of medicinal plants, 120 taxa (31.2%) of pasture plants, 52 taxa (13.5%) of ornamental plants, 16 taxa (4.2%) of timber plants, 4 taxa (1.0%) of fiber plants and 3 taxa (0.8%) of industrial plants.

• Journal of the Korean Institute of Telematics and Electronics B
• /
• v.31B no.7
• /
• pp.66-75
• /
• 1994

In this paper, we present a new GPC algorithm for plants with known disturbances. Also, based on the above algorithm unidirectional and bidirectional predictive controllers have been proposed concerning plants with input couplings between subprocesses. These predictive control algorithms can be applied to many industrial processes as a multiloop controllers. Simulation results show that the proposed algorithm has improved performance and computing time compared to conventional GPC algorithm.