• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.10 no.8
• /
• pp.3884-3910
• /
• 2016

Intrusion Detection System (IDS) in general considers a big amount of data that are highly redundant and irrelevant. This trait causes slow instruction, assessment procedures, high resource consumption and poor detection rate. Due to their expensive computational requirements during both training and detection, IDSs are mostly ineffective for real-time anomaly detection. This paper proposes a dimensionality reduction technique that is able to enhance the performance of IDSs up to constant time O(1) based on the Principle Component Analysis (PCA). Furthermore, the present study offers a feature selection approach for identifying major components in real time. The PCA algorithm transforms high-dimensional feature vectors into a low-dimensional feature space, which is used to determine the optimum volume of factors. The proposed approach was assessed using HTTP packet payload of ISCX 2012 IDS and DARPA 1999 dataset. The experimental outcome demonstrated that our proposed anomaly detection achieved promising results with 97% detection rate with 1.2% false positive rate for ISCX 2012 dataset and 100% detection rate with 0.06% false positive rate for DARPA 1999 dataset. Our proposed anomaly detection also achieved comparable performance in terms of computational complexity when compared to three state-of-the-art anomaly detection systems.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.67 no.2
• /
• pp.173-178
• /
• 2018

This study organizes scenarios on the power supply and demand plans considering the uncertainties and the portion of distributed energy resources. In analysing the scenarios, it estimates total electricity supply cost in the social aspect, natural gas demand and air pollutants emission including carbon dioxide. Also the analysis is performed to estimate the marginal cost of carbon dioxide reduction for the fuel switching from coal to liquified natural gas. In result, the social cost could be decreased by replacing some portion of renewable energy by LNG-based combined heat and power and delaying the construction of large base-load generators such as coal and nuclear plants. The marginal carbon dioxide reduction cost by fuel switching is in plausible range for fuel switching to be an option for carbon dioxide emission reduction when the social cost is considered.

• Journal of the Korean Applied Science and Technology
• /
• v.26 no.4
• /
• pp.483-490
• /
• 2009

This research was conducted to estimate the characteristics of carbon dioxide decomposition using an inorganic sludge. The inorganic sludge was composed of high amount (66.8%) of $Fe_2O_3$. Hydrogen could be reduced with 0.247, 0.433, 0.644, and 0.749 at 350, 400, 450, and $500^{\circ}C$, respectively. The carbon dioxide decomposition rates at 250, 300, 350, 400, 450, and $500^{\circ}C$ were 32, 52, 35, 62, 75, and 84%, respectively. High temperature led to high reduction of hydrogen and better decomposition of carbon dioxide. The specific surface area of the sludge after hydrogen reduction was higher than that after carbon dioxide decomposition. The specific surface area of the sludge was more decreased with increasing of temperature.

• Journal of the Korea Safety Management & Science
• /
• v.11 no.2
• /
• pp.145-152
• /
• 2009

As the industry develops, the amount of wastes is increasing in the economic system with various needs. As a result, the environmental problems are emerging as serious social issues and all the parties are required to make their best efforts. Among the issues proposed as the environmental issues, the logistics-related issues are exhaustion of the resources, global warming, environmental pollution, and acidification and so on. In order to respond to the environmental issues of the earth, the advanced countries are setting retrenched goals, reduction of the new greenhouse gases and accomplishment of retrenched goals by cooperation between the nations. Economic activities inevitably bring environmental problems and logistics is implementing those activities. The companies should perform the roles to resolve the environmental problems as the main cause of environmental pollution. Therefore, along with spreading recognition of social demand, the companies are required to establish policies regarding the environment and they should approach the issues from the perspective of resource circulation. These environment-friendly activities are emerging as the new source of competitiveness in the logistics field. Therefore, this study analyzes the effects of environment-friendly logistics activities on the reduction of logistics cost to reduce and resolve the environmental issues such as environment preservation, recycling and so on.

• Design & Manufacturing
• /
• v.13 no.4
• /
• pp.17-22
• /
• 2019

Currently, studies on weight reduction and fuel efficiency increase are the most important topics in the automotive industry and many studies are under way. Among them, weight reduction is the best way to raise fuel efficiency and solve environmental pollution and resource depletion. Materials such as aluminum, magnesium and carbon curing materials can be found in lightweight materials. Among these, research on improvement of bonding technology and manufacturing method of materials and improvement of material properties through study of ultrahigh strength steel sheet is expected to be the biggest part of material weight reduction. As the strength of the ultra hight strength steel sheet increases during forming, it is difficult to obtain the dimensional accuracy as the elastic restoring force increases compared to the hardness or high strength steel sheet. It is known that the spring back phenomenon is affected by various factors depending on the raw material and processing process. We have conducted analytical evaluations and studies to analyze the springback that occurs according to the cross-sectional shape of the ultra high tensile steel sheet.

• International Journal of Quality Innovation
• /
• v.6 no.2
• /
• pp.59-89
• /
• 2005

Manufacturing Resources Planning (MRPII) is one kind of manufacturing information system that can help manufacturing companies gain competitive advantages. It is estimated that more than one hundred MRPII systems are available in the market, many of them are mature enough to solve most operational issues in accordance with users' requirements. More often than not, many of these systems provide more functions than a company expects. Manufacturing companies worldwide have attempted to implement these MRPII systems, however, many companies experienced failure (Turbide, 1996) due to managerial rather than technical issues. The authors propose an approach utilising a roadmap to integrate BPR and the MRPII implementation in order to overcome this difficulty. A detail road map is developed to guide this implementation, which is designed using a hierarchical analysis technique known as Integrated DEFinition Method (IDEF). IDEF is a systematic manufacturing management and integration-modeling tool. The proposed approach is implemented and illustrated using a reference company and the results indicated that 66% reduction in errors for maintaining the bills of materials system; 99% reduction in time to carry out material requirement planning; and 70% reduction in time previously taken for non-productive discussions.

• Resources Recycling
• /
• v.27 no.2
• /
• pp.68-76
• /
• 2018

EAF (Electric arc furnace) dust is an important secondary resource such as zinc, lead, and iron. Recycling of EAF dust is benefit to solving disposal and environmental problems caused by the heavy metals entrained in the dust. In this study, pyrometallurgical treatment technology of EAF dust reviewed for the improvement of conventional process and development of new process. The existing technologies categorized into four groups: those by rotary kiln process, rotary hearth furnace (RHF) process, shaft type process, and reduction smelting process. The product of these processes are ZnO and Fe or slag as a waste. Their mechanisms for the production of ZnO from EAF dust were carbothermic reduction and oxidation of zinc gas with air.

• Journal of The Korean Society of Agricultural Engineers
• /
• v.52 no.1
• /
• pp.69-77
• /
• 2010

Research on permeable pavement like asphalt and concrete pavement with porous structure has been increasing due to environmental and functional need such as reduction of run off and flood, and increase and purification of underwater resource. This study was performed to evaluate permeability, strengths and durability of permeable polymer concrete (PPC) using recycled aggregate that is obtained from waste concrete. Also, 6mm length of polypropylene fiber was used to increase toughness and interlocking between aggregate and aggregate surrounded by binder. In the test results, regardless of kinds of aggregates and fiber contents, the compressive strength and permeability coefficient of all types of PPC showed the higher than the criterion of porous concrete that is used in permeable pavement in Korea. Also, strengths of PPC with increase polypropylene fiber volume fraction showed slightly increased tendency due to increase binder with increase of fiber volume fraction. The weight reduction ratios for PPC after 300 cycles of freezing and thawing were in the range of 1.6~3.8 % and 2.2~5.6 %, respectively. The weight change ratio was very low regardless of the fiber volume fraction and aggregates. The weight reduction ratios of PPC with fiber and aggregate were in the range of 1.3~2.7 % and 2.2~3.2 % after 13 weeks and was very low regardless of the fiber volume fraction and aggregates.

• Journal of the Korean Solar Energy Society
• /
• v.31 no.4
• /
• pp.1-8
• /
• 2011

In this paper, inverse building modeling was applied to building perimeter zones which have different window orientation. Two test zones of east-facing and west-facing zones in ERS(Energy Resource Station) building, which is representative of small commercial building, was used to test performance of cooling load calculation and peak cooling load reduction. The dynamic thermal load model for the east and west zone was validated using measured data for the zones and then it was used to investigate the effect of peak cooling load reduction by adjustment of indoor cooling temperature set points during on-peak time period. For the east zone, the peak load can be reduced to about 60% of the peak load for conventional control even without any precooling. For the west zone, PLR is nearly independent of the start of the on-peak period until a start time of 1pm. Furthermore, PLR has a small dependence on the precooling duration. Without any precooling, the peak cooling load can be reduced to about 35% of the peak load associated with conventional control.

• Environmental and Resource Economics Review
• /
• v.22 no.4
• /
• pp.691-726
• /
• 2013

We develop a hybrid model which allows the change in electricity generation mix by adding the electricity-sector components of bottom-up model to the conventional CGE model. The electricity sector is represented as a sum of separate generation technologies, each of which has the form of DRTS (Decreasing Returns to Scale) production function, unlike the conventional CGE model. We compare the effects of the 30% emission reduction target using the hybrid model with those using the conventional CGE model. The cost of meeting the target is lower with the hybrid model than the conventional CGE. It is consistent with previous studies in that adding the bottom-up components to the top-down model reduces the cost of emission reduction. In an extra analysis we find that an additional regulation like RPS (Renewable Portfolio Standard) increases the cost.