• Environmental and Resource Economics Review
• /
• v.9 no.5
• /
• pp.811-827
• /
• 2000

Since improved thermal efficiency reduces capacity requirements and energy costs, electricity producers often treat thermal efficiency as a measure of management or economic performance. The conventional measure of the thermal efficiency of a fossil-fuel generation system is the ratio of total electricity generation to the simple sum of energy inputs. As a refined approach, we present a novel thermal efficiency measure using the concept of the Divisia index number. Application of this approach to the Korean power sector shows improvement of thermal efficiency of 1.1% per year during 1970-1998. This is higher than the 0.9% improvement per year given by the conventional method. The difference is attributable to the effect of fuel substitution. In the Divisia decomposition context, we also show the limitations of the popular $T{\ddot{o}}rnqvist$ index formula and the superiority of the Sato-Vartia formula.

• Journal of Korea Multimedia Society
• /
• v.7 no.6
• /
• pp.767-780
• /
• 2004

Interaction requires dynamic relationship between objects. In ubiquitous computing environment, interaction between human and the environment is implied. Tactile interaction has so far been less addressed, while tactile sensation should be an important topic in the field of multimedia study. This paper describes development of a novel PVDF (Polyvinylidene Fluoride) dynamic tactile sensor and associated experiments. PVDF dynamic tactile sensors detect touch events applied to the sensor skin by low frequency components of the signal. Rubber skin-covered sensing material was mounted on the bones. Robust performance with low noise was figured out in our robotic experiment. Whereas most conventional sensors are interested in measurement, our dynamic tactile sensor is sensitive to change of state, which could be a key for economic understanding of happenings in the dynamic world. We note that dynamic sensing uses motion as a part of sensing modality We suggest that dynamic sensing be understood in technological terms in the perspective of interactive media and ubiquitous computing.

• Structural Engineering and Mechanics
• /
• v.47 no.1
• /
• pp.99-118
• /
• 2013

Earthquakes, which are unavoidable natural phenomena in Turkey, have often produced economic and social disaster. The latest destructive earthquakes happened in Van city. Van, Turkey, earthquakes with M = 7.2 occurred on 23 October 2011 at 13:41 (local time), whose epicenter was about 16 km north of Van (Tabanlivillage) and M = 5.6 on 9 November 2011 epicentered near the town of Edremit south of Van in eastern Turkey and caused the loss of life and heavy damages. Both earthquakes killed 644 people and 2608 people were injured. Approximately 4000 buildings collapsed or were seriously damaged. The majority of the damaged structures were seismically insufficient, unreinforced masonry and adobe buildings in rural areas. In this paper, site surveys of the damaged masonry and adobe buildings are presented and the reasons for the caused damages are discussed in detail.

• Computers and Concrete
• /
• v.26 no.6
• /
• pp.577-585
• /
• 2020

By the increasing amount of waste materials, it eventually dumped into the environment and covering a larger area of the landfill which cause several environmental pollution problems. The utilization of Palm Kernal Shell Ash (PKSA) in concrete might bring a great benefit in addressing both environmental and economic issues. This article investigates the effect of PKSA as a partial cement replacement of High Strength Concrete (HSC). Several concrete mixtures were prepared with different PKSA of 0%, 10%, 20%, and 30% replaced by the cement mass. This procedure was replicated twice for the two different target mean strengths of 40 MPa and 50 MPa. The mixtures were prepared to test different fresh and hardened properties of HSC including slump test, the compressive strength of 3, 7, 14, 28, and 90 days, flexural strength of 28-days, drying shrinkage, density measurement, and sorptivity. It was observed 10% PKSA replacement as optimum percentage which reduced the drying shrinkage, sorptivity, and density and improved the late-age compressive strength of concrete.

• International conference on construction engineering and project management
• /
• 2005.10a
• /
• pp.1199-1202
• /
• 2005

Knowledge has been considered one of the important elements that determine our future. Competitive power of an enterprise has also been transformed from labor, capital, and technology-oriented to knowledge-oriented. Current construction environment is experiencing overall decrease of number of construction contracts due to opening of domestic construction market and economic slump, problems on methods of receiving orders/bidding, and change of costumers' attitude, which intensify competition, therefore many companies consider adopting knowledge management to secure their competitive power. However, there are difficulties in adopting knowledge management and increasing the use by establishing management plan, Performance Measurement, and knowledge maintenance system in reality. Therefore, this study is to provide assistance to successful realization of knowledge management by suggesting development plan of knowledge management that enables knowledge management more efficient with certain goals.

• Journal of the Korea Institute of Building Construction
• /
• v.22 no.2
• /
• pp.207-218
• /
• 2022

Changes in megatrends occurring within the spatial range of the production process can be critical factors that affect the performance of unit projects in construction industry, one of the representative order industries. Although changes in the megatrend are a prerequisite for successful performance achievement, previous studies suggested methods for performance measurement and management within the production process as major results. Accordingly, this study analyzed the megatrend related to domestic construction projects and presented critical impact factors(CIFs) that can be affect a project's performance. CIFs were set by combining keywords derived by reviewing major contents of related laws and policies and future strategy reports, and the importance of each indicator was quantitatively analyzed using analytic hierarchy process(AHP). It is expected that the findings of this study can provide meaningful basic data that the various stakeholders in a construction project can refer to when establishing the strategies to achieve successful performance.

• Journal of the Korean Society for Library and Information Science
• /
• v.50 no.4
• /
• pp.121-142
• /
• 2016

The purpose of this study was to assess the economic value of the National Assembly Library service utility, and to enhance the users' perception and the stakeholder's supports for the library services. For those purposes, this study applied the measurement methods of time value, replacement service value, and WTP of the three user groups: inside members, outside users, and institutional members of the Library. The replacement service value as annual time valuation was measured 1,948.2 million won by inside members, and 417.057.5 million won by outside users, that was approximately 10 times of the total budget of the year 2015. Also, WTP were measured as 8,528.3 million won by inside member, 33,272.4 million won by outside users, 924 million won by institutional members. This shows 77% of the use value were from outside users. The BC ratio was 1:1.04 in 2015.

• Journal of Korea Port Economic Association
• /
• v.36 no.2
• /
• pp.53-62
• /
• 2020

The maritime and port logistics industry is closely related to global trade and economic activity, especially for Korea, which is highly dependent on trade. As the largest port in Korea, Busan Port processes 75% of the country's container cargo; the port is therefore extremely important in terms of the country's national competitiveness. Port container cargo volume forecasts influence port development and operation strategies, and therefore require a high level of accuracy. However, due to unexpected and sudden changes in the port and maritime transportation industry, it is difficult to increase the accuracy of container volume forecasting using existing time series models. Among deep learning models, this study uses the LSTM model to enhance the accuracy of container cargo volume forecasting for Busan Port. To evaluate the model's performance, the forecasting accuracies of the SARIMA and LSTM models are compared. The findings reveal that the forecasting accuracy of the LSTM model is higher than that of the SARIMA model, confirming that the forecasted figures fully reflect the actual measurement figures.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.32 no.12C
• /
• pp.1175-1187
• /
• 2007

This paper proposes a novel crest factor reduction (CFR) algorithm to be deployed on WCDMA basestation. Generally speaking, it is well described that the reduction of peak-to-average ratio (PAR) yields the possibility of using low cost power amplifier such that the basesation becomes economic However, the simple reduction of PAR could degrade the signal quality measured by either peak code domain error (PCDE) or error vector measurement (EVM), and the level of channel interference constrained by adjacent channel leakage ratio (ACLR). Regarding these imperfections, this paper introduces an effective CFR algorithm in which the function of filter-dependent CFR (FDCFR) incorporated with the histogram-based waterfilling code domain compensation (HBWCDC) carries out. To verify the performance of the proposed CFR technique, substantial simulations including comparative works are conducted with obeying W-CDMA basestation verification specification. To exploit the superiority, the performance of the proposed method is tentatively compared with that associated to the simple memoryless clipping method and the memory-required filter-dependent clipping method.

• Korean Journal of Construction Engineering and Management
• /
• v.19 no.2
• /
• pp.38-49
• /
• 2018

Since the ratification of the Paris Agreement (COP21), the government is continuously strengthening policies for the reduction of greenhouse gas of the construction industry in accordance with the growing importance of reducing greenhouse gas and obligation of the government. Especially, the government emphasizes the need to improve the energy performance of old public buildings. Since 2014, the government is running a pilot project in which the government supports the construction cost of the green remodeling project of old public buildings and it is intended to develop the best practice of green remodeling and activate the green remodeling in the private sector. In this study, we analyzed the economical efficiency of the old public buildings by each level through green remodeling and conducted building related investigation and equipment measurement to plan the alternatives of the corresponding buildings. The improvement plan is a green remodeling plan that integrates alternatives. Five improvement plans were developed for each level to analyze the economic feasibility of each plan. As for the analysis method, the first energy demand amount calculation and the LCC analysis were performed through ECO2. In the LCC aspect, the improved 3/4 plan (middle level plan) was the most excellent and results were obtained in the order of the highest cost plan followed by the lowest cost plan. As a result, it is expected that it can be utilized as a basic data for future green remodeling performance plan and economic feasibility analysis in the future.