• Journal of the Economic Geographical Society of Korea
• /
• v.18 no.1
• /
• pp.1-16
• /
• 2015

It is widely believed that increasing socio-economic polarization inspired by globalization and economic restructuring worsens residential segregation by class in Korean cities. However, the existing literature falls short in showing the recent changes of the residential segregation, particularly after the 1997 financial crisis, with reliable and systematic segregation measures. Noting that there are the two major dimension in residential segregation - evenness-concentration and exposure-clustering - this study introduced not only global measure (dissimilarity index and isolation/interaction index) but also local measures (location quotient and Local Moran's I) for each dimension. These measures are applied to the case study of Seoul in the 2000s. The class is defined by education attainment and the data is obtain through the MicroData System Service System(MDSS). The result shows that the residential segregation by education attainment persists through 2000s and even get worse in some dimension. More significantly, it turns out that high-class and low-class residence are nearly mirror-images of each other, indicating high segregation.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.59 no.12
• /
• pp.2165-2172
• /
• 2010

This paper presents the operation algorithm of microgrid on the Real Time Pricing(RTP) for building the smart grid. RTP is higher power price variability than flat rate and time of use. However it has an effect on peak clipping and peak load shifting due to the increased price on peak time power demand. When the RTP are applied to the microgrid system, the proposed algorithm is able to be effective and economic operation. The implemented system is operated for the economic operation in microgrid connected with the power system. On the other hand, when the microgrid is operated on isolation mode, it focus on the improvement of stability and the power supply reliability of the sensitive loads. The test system are implemented and calculated on various operation modes based on non-dispachable generator output and RTP data for validating the proposed operation algorithm. The calculated results are compared to the implemented results using real-time simulator. It can be confirmed that the proposed operation system are identical results to the calculated one. When the proposed operation algorithm is applied to the system, it can be show the effectiveness of the peak clipping and peak load shifting and the improvement of economic feasibility.

• Journal of Digital Convergence
• /
• v.19 no.2
• /
• pp.133-141
• /
• 2021

Recently, the number of seniors who engage in social and economic activities through digital platforms is increasing. Through this, they are building new social networks or creating profits. Therefore, this study aimed to conduct an in-depth interview with 17 seniors who are engaged in social and economic activities on a digital platform. This study examined their motivation and experience in detail through in-depth interviews. As a result of the study, three subjects (motivation for participation, evaluation and performance of activities, and requirements for stable activities) were derived. The results of this study are predicted to contribute to preventing social isolation of seniors by mediating digital platforms in the future and inducing them to become subjects of the digital economy.

• Journal of Advanced Research in Ocean Engineering
• /
• v.2 no.4
• /
• pp.158-168
• /
• 2016

During the installation of crude oil or gas pipelines, which pass through onshore buried pipelines or onshore pipeline from subsea pipeline to onshore plant, countermeasures need to be implemented so as to ensure a sufficient design life by protecting the steel pipes against corrosion. This can be achieved through impressed current cathodic protection method for onshore pipelines and through galvanic sacrificial anode corrosion protection method for offshore pipelines. In particular, in the case of impressed current cathodic protection, isolation joint flanges should be used. However, this makes maintenance control difficult with its installation having a negative impact on price. Therefore, in this study, the most suitable methodology for onshore pipeline protection between galvanic sacrificial anode corrosion protection and impressed current cathodic protection method will be introduced. In oil and gas transportation facilities, the media can be carried to the end users via onshore buried and/or offshore pipeline. It is imperative for the field operators, pipeline engineers, and designers to be corrosion conscious as the pipelines would undergo material degradations due to corrosion. The mitigation can be achieved with the introduction of an impressed current cathodic protection method for onshore buried pipelines and a galvanic sacrificial anode corrosion protection method for offshore pipelines. In the case of impressed current cathodic protection, isolation joint flanges should be used to discontinuity. However, this makes maintenance control to be difficult when its installation has a negative impact on the price. In this study, the most suitable corrosion protection technique between galvanic sacrificial anode corrosion protection and impressed current cathodic protection is introduced for (economic life of) onshore buried pipeline.

• Journal of Digital Convergence
• /
• v.16 no.12
• /
• pp.109-122
• /
• 2018

This study investigates factors to disturb the e-Learning persistence of adult learners based on a case study of Cyber University students located in Seoul Korea. Main findings of our research show that economic burden, shortage of studying hours, digital literacy problem, perceived isolation, inefficient interaction between lecturer and student, and support of family are primary factors to influence the persistence of online education in a Cyber university. From our case study, we recommend to improve the scholarship system, and supplement the offline special lectures at weekends in order to alleviate perceived isolation. A novelty of this paper is that economic burden is highlighted to influence the persistence of adult learners.

• Journal of Korean Academy of Nursing
• /
• v.27 no.2
• /
• pp.444-453
• /
• 1997

The purpose of this study was to construct a grounded theory as the basis for nursing intervention by describing and analysing the holistic lived experiences of clients receiving long-term hemodialysis. The subjects of this study were fifteen persons receiving regular hemodialysis regimen at artificial kindey treatment centers in two different university hospitals, and who were able to participate in conversation and were available for long and dup interviews. Eight of the subjects were male and seven were female and their ages ranged from 30's to 60's. The length of the hemodialysis experience ranged from two months to six years. The collection and analysis of data were done in accordance with the grounded theory methodology of Strauss & Corbin. The method to collect the data mainly depended. on long and deep interviews, participant observation and focused group interviews and the equipment used to collect data were a portable tape recorder and field notes. The study is summarized as follows : 1. The meaning of holistic lived experiences of clients receiving long -term hemodialysis was found to be uncertainty. which was identified as the core category. 2. The main categories following the core category were found to be shock, ambiguity, social support and quality of life. 3. Through the main category the type of behavior newly formed by clients receiving long-term hemodialysis was found to be as follows. That is to say, in the circumstances of shock caused by the identified fact and the ambiguity of hemodilysis they formed a quality of life based on social support, which was found to be a kind of chaotic phenomenon. 4. The lived experiences of clients receiving long-tern hemodialysis was found to include nine categories : emotional shock, feelings of isolation, burden, unclearness, dependency, help from others, coping strategies, maintenance of self-esteem and transitional life. 5. The intervening factors influencing each category are as follows : 1) The factors influencing 'emetional shock' were found to be set age, the level of knowledge received in advance, locus of control, the period of struggle against the disease before hemodialysis and whether any serious illness existed. 2) The factors influencing 'feelings of isolation' were found to be religion and the length of the hemodialysis experience. 3) The factors influencing 'burden' were found to be sex, economic situation, employment status and the length of the hemodialysis experience. 4) The factors influencing 'unclearness' were found to be sex, age, religion. economic situation, the length of the hemodiaysis experience, whether they had had a transfusion and whether there were any complications. 5) The factors influencing 'help from others' were found to be religion. economic situation, past experiences and whether family members lived together. 6) The factors influencing 'coping strategies' were foung to be age, level of education, experiences of illness and locus of control. 7) The factors influeruing 'maintenance of self-esteem' were found to be the length of the hemodialysis experience and self-actualization. 8) The factors influencing 'transitional life' were found to be age, religion, economic situation, employment status. locus of control. past experiences and whether there was a plan for a kidney transplant.

• Advances in environmental research
• /
• v.9 no.3
• /
• pp.215-232
• /
• 2020

Crude oils are essential source of energy. It is majorly found in geographical locations beneath the earth's surface and crude oil is the main factor for the economic developments in the world. Natural crude oil contains unrefined petroleum composed of hydrocarbons of various molecular weights and it contains other organic materials like aromatic compounds, sulphur compounds, and many other organic compounds. These hydrocarbons are rapidly getting degraded by biosurfactant producing microorganisms. The present study deals with the isolation, purification, and characterization of biosurfactant producing microorganism from oil-contaminated soil. The ability of the microorganism producing biosurfactant was investigated by well diffusion method, drop collapse test, emulsification test, oil displacement activity, and blue agar plate method. The isolate obtained from the oil contaminated soil was identified as Bacillus subtilis. The identification was done by microscopic examinations and further characterization was done by Biochemical tests and 16SrRNA gene sequencing. Purification of the biosurfactant was performed by simple liquid-liquid extraction, and characterization of extracted biosurfactants was done using Fourier transform infrared spectroscopy (FTIR). The degradation of crude oil upon treatment with the partially purified biosurfactant was analyzed by FTIR spectroscopy and Gas-chromatography mass spectroscopy (GC-MS).

• Earthquakes and Structures
• /
• v.14 no.5
• /
• pp.389-398
• /
• 2018

The seismic isolation system makes a structure isolated from ground motions to protect the structure from seismic events. Seismic isolation techniques have been implemented in full-scale buildings and bridges because of their simplicity, economic effectiveness, inherent stability and reliability. As for the responses of an isolated structure due to seismic events, it is well known that the most uncertain aspects are the seismic loading itself and structural properties. Due to the randomness of earthquakes and uncertainty of structures, seismic response distributions of an isolated structure are needed when evaluating the seismic fragility assessment (or probabilistic seismic safety assessment) of an isolated structure. Seismic response time histories are useful and often essential elements in its design or evaluation stage. Thus, a large number of non-linear dynamic analyses should be performed to evaluate the seismic performance of an isolated structure. However, it is a monumental task to gather the design or evaluation information of the isolated structure from too many seismic analyses, which is impractical. In this paper, a new methodology that can evaluate the seismic fragility assessment of an isolated structure is proposed by using stochastic response database, which is a device that can estimate the seismic response distributions of an isolated structure without any seismic response analyses. The seismic fragility assessment of the isolated nuclear power plant is performed using the proposed methodology. The proposed methodology is able to evaluate the seismic performance of isolated structures effectively and reduce the computational efforts tremendously.

• Journal of Korean Society on Water Environment
• /
• v.25 no.6
• /
• pp.872-878
• /
• 2009

Advanced Phase Isolation Ditch (APID) process was studied to develop economic retrofitting technology, for the plants where retrofitting of common activated sludge process is required. In this study, to develop and apply the modified intermittently aeration mode as process control conditions for treating municipal wastewater, a demonstration plant was installed and operated in the existing sewage treatment plant of P city. During this study, the average effluent $BOD_5$, SS, T-N, and T-P concentrations were 6.3, 4.5, 10.0, and 1.3 mg/L. The modified mode decreased the nitrification capability more than the conventional mode in the application period. Nitrate in the anaerobic condition can have a negative effect on biological phosphorus removal. In the decreasing nitrate levels, the modified mode increased the biological ability of removal phosphorus more than the conventional mode in this study. Therefore, newly developed APID process with modified intermittent aeration mode can be one of the useful processes for stable organic matter and nutrients removal.

• Earthquakes and Structures
• /
• v.9 no.5
• /
• pp.937-956
• /
• 2015

Seismic isolation systems decouple structures from ground motions to protect them from seismic events. Seismic isolation devices have been implemented in many full-scale buildings and bridges because of their simplicity, economic effectiveness, inherent stability, and reliability. It is well known that the most uncertain aspect for obtaining the accurate responses of an isolated structure from seismic events is the seismic loading itself. It is needed to know the seismic response distributions of the isolated structure resulting from the randomness of earthquakes when probabilistic designing or probabilistic evaluating an isolated structure. Earthquake time histories are useful and often an essential element for designing or evaluating isolated structures. However, it is very challenging to gather the design and evaluation information for an isolated structure from many seismic analyses. In order to evaluate the seismic performance of an isolated structure, numerous nonlinear dynamic analyses need to be performed, but this is impractical. In this paper, the concept of the stochastic response database (SRD) is defined to obtain the seismic response distributions of an isolated structure instantaneously, thereby significantly reducing the computational efforts. An equivalent model of the isolated structure is also developed to improve the applicability and practicality of the SRD. The effectiveness of the proposed methodology is numerically verified.