• Journal of Korean Society of Occupational and Environmental Hygiene
• /
• v.33 no.2
• /
• pp.93-102
• /
• 2023

Objectives: With the evolution of direct reading sensors, it is possible to monitor several substances through telecommunication. However, there are some limitations on the use of direct reading technologies in the Occupational Safety and Health Act in South Korea, which only applies to detector tubes, noise, heat, and carbon monoxides. The number of chemicals and their amount of use have been continuously increasing in South Korea. The Ministry of Employment and Labor (MoEL) has concerns about worker's health because exposure is only covered for about 1.2% of all distributed chemicals. Using a direct reading monitor with photoionization detectors (PID-DRMs), gases and vapors chemicals can be measured. Based on the data, business owners are able to create corrective strategies, provide better working routines, and select correct respiratory equipment. PID-DRMs are less expensive and easier to handle for an owner voluntarily controlling chemicals emitted in the workplace. However, there are several limitations on using these PID-DRMs to the degree that the MoEL has not been able to select a legal monitor. The aim of this study was to review previous studies related to PID-DRMs and identify the characterization and limitation on PID-DRMs. Methods: To search for related studies on PID-DRMs, key words were used including direct reading monitors/instruments and/or photoionization detectors. Through that, four domestic and 15 international studies were reviewed. Results: Studies on PID-DRMs were conducted by chamber (enclosed, dynamic, walk-in) and in the field (experimental environment, actual environment). The concentration of PID-DRMs and charcoal tubes were compared for a single substance or mixture, or within the PID-DRMs. There was a high correlation between the two concentrations, but it did not meet the accuracy criteria (95% confidence interval, within 25%) of the NIOSH technical report (2012). In addition, differences in measured values occurred according to environmental factors (temperature, humidity) and high concentration, and concentration values tended to be underestimated due to contamination of the sensor. As a way to improve the accuracy of PID concentration, it was proposed to use correction factors, charcoal tube-based correction factors, or to calibrate the PID-DRMs in the same environment as the workplace. Conclusions: PID-DRMs can likely be used by business owners for the purpose of voluntarily managing the workplace environment, and it is expected that it will be possible to use them as legal equipment if a PID sensor can be upgraded and the limitations of the sensor (temperature, humidity, high concentration evaluation, sensor pollution) can be overcome in the near future.

• Journal of the Computational Structural Engineering Institute of Korea
• /
• v.15 no.4
• /
• pp.591-598
• /
• 2002

In the ship structural design, the material cost of hull weight and the overall cost of construction processes should be minimized considering safety and reliability. In the past, minimum weight design has been mainly focused on reducing material cost and increasing dead weight reflect the interests of a ship's owner. But, in the past experience, the minimum weight design has been inevitably lead to increasing the construction cost. Therefore, it is necessary that the designer of ship structure should consider both structural weight and construction cost. In this point of view, multi-objective optimization technique is proposed to design the ship structure in this study. According to the proposed algorithm, the results of optimization were compared to the structural design of actual VLCC(Very Large Crude Oil Carrier). Objective functions were weight cost and construction cost of VLCC, and ES(Evolution Strategies), one of the stochastic search methods, was used as an optimization solver. For the scantlings of members and the estimations of objectives, classification rule was adopted for the longitudinal members, and the direct calculation method, GSDM(Generalized Slope Deflection Method), lot the transverse members. To choose the most economical design point among the results of Pareto optimal set, RFR(Required Freight Rate) was evaluated for each Pareto point, and compared to actual ship.

• Fisheries and Aquatic Sciences
• /
• v.9 no.2
• /
• pp.70-74
• /
• 2006

DNA sequence-based typing is considered a robust tool for the discrimination of dinoflagellate species because of the availability of extensive rDNA sequences. Here, we present a rapid, cost-effective DNA-sequencing technique for various PCR products. This sequencing strategy relies on 'nested' or 'tailed' primer labeled with near-infrared dye, and uses a minimal volume of unpurified PCR product (ca. $5{\mu}L$) as the DNA template for sequencing reactions. Reliable and accurate base identification was obtained for several hundred PCR fragments of rRNA genes. This quick, inexpensive technique is widely applicable to sequence-based typing in clinical applications, as well as to large-scale DNA sequencing of the same genomic regions from related species for studies of molecular evolution.

• 한국연소학회:학술대회논문집
• /
• 2006.10a
• /
• pp.177-186
• /
• 2006

Flame surface area is a critical parameter determining turbulent flame speed. Three-dimensionaldirect numerical simulations (DNS) were conducted to figure out the evolution process of flame surface area. Fully compressible Navier-Stokes equations are solved to reproduce premixed flame embedded in isotropic decaying turbulent flow. The tangential straining and curvature of propagating surface affect development of flame area. In this study, four different turbulent intensity flows and three different Le number flames are investigated to force changes in straining and curvature effects. Consistent results are obtained for the probability density functions (PDF) of strain and curvature with previous researches. It is revealed that displacement speed, which is a speed of flame surface relative to unburnt flow, controls the balance between sink and source of flame surface area.

• Asian Journal of Innovation and Policy
• /
• v.4 no.1
• /
• pp.103-127
• /
• 2015

This paper investigates the two academic revolutions of the Korean higher education system. Since economic catch-up began in the 1960s, Korea has strongly encouraged the activities of its higher education system to serve industrial development as it has progressed through various developmental stages. At the 'strong regulation' stage, universities focused on the provision of technicians. As the need for higher education grew, the 'massive expansion' stage emerged. Finally, most recently, university research and its direct contribution to the economy have been invigorated by strong governmental support. Possibly, this is due to the fact that the Korean government has strongly controlled not only industry but also academia. As long as other East Asian universities have similar conditions to those of the development of Korean universities, we can generalise this model not only to universities in other East Asian countries, but also to universities in other rapid catch-up countries.

• The Bulletin of The Korean Astronomical Society
• /
• v.40 no.2
• /
• pp.50.4-51
• /
• 2015

Current and planned deep multicolor wide-area cosmological surveys will map in detail the spatial distribution of galaxies and quasars over unprecedented volumes, and provide a number of objects with photometric redshifts more than an order of magnitude bigger than that of spectroscopic redshifts. Photometric information is statistically more significant for studying cosmological evolution, dark energy, and the expansion history of the universe at a fraction of the cost of a full spectroscopic survey, but intrinsically carries a bias due to noise in the distance estimates. We provide convolution- and deconvolution-based algorithms capable of removing this bias -- thus able to exploit the full cosmological information -- in order to reconstruct intrinsic distributions and correlations between distance-dependent quantities. We then show some direct applications of our techniques to the VIMOS Public Extragalactic Redshift Survey (VIPERS) and the Sloan Digital Sky Survey (SDSS) datasets. Our methods impact a broader range of studies, when at least one distance-dependent quantity is involved; hence, they will be useful for upcoming large-volume surveys, some of which will only have photometric information.

• Clinical and Experimental Pediatrics
• /
• v.50 no.9
• /
• pp.835-840
• /
• 2007

Any infant noted to be jaundiced at 2 weeks of age should be evaluated for cholestasis with measurement of total and direct serum bilirubin. With the insight into the clinical phenotype and the genotype-phenotype correlations, it is now possible to evaluate more precisely the neonate who presents with conjugated hyperbilirubinemia. Testing should be performed for the specific treatable causes of neonatal cholestasis, specifically sepsis, galactosemia, tyrosinemia, citrin deficiency and endocrine disorders. Biliary atresia must be excluded. Low levels of serum gamma-glutamyl transferase in the presence of cholestasis should suggest progressive familial intrahepatic cholestasis type 1, 2, or arthrogryposis- renal dysfunction-cholestasis syndrome. If the serum bile acid level is low, a bile acid synthetic defect should be considered. Molecular genetic testing and molecular-based diagnostic strategies are in evolution.

• Wind and Structures
• /
• v.13 no.2
• /
• pp.191-206
• /
• 2010

Windborne debris is a major cause of structural damage during severe windstorms and hurricanes owing to its direct impact on building envelopes as well as to the 'chain reaction' failure mechanism it induces by interacting with wind pressure damage. Estimation of debris risk is an important component in evaluating wind damage risk to residential developments. A debris risk model developed by the authors enables one to analytically aggregate damage threats to a building from different types of debris originating from neighboring buildings. This model is extended herein to a general debris risk analysis methodology that is then incorporated into a vulnerability model accounting for the temporal evolution of the interaction between pressure damage and debris damage during storm passage. The current paper (Part I) introduces the debris risk analysis methodology, establishing the mathematical modeling framework. Stochastic models are proposed to estimate the probability distributions of debris trajectory parameters used in the method. It is shown that model statistics can be estimated from available information from wind-tunnel experiments and post-damage surveys. The incorporation of the methodology into vulnerability modeling is described in Part II.

• Environmental Engineering Research
• /
• v.19 no.4
• /
• pp.299-308
• /
• 2014

This study presents a review on Chemical looping combustion (CLC) development, design aspects and modeling. The CLC is in fact an unmixed combustion based on the transfer of oxygen to the fuel by a solid oxygen carrier material avoiding the direct contact between air and fuel. The CLC process is considered as a very promising combustion technology for power plants and chemical industries due to its inherent capability of $CO_2$ capturing, which avoids extra separation costs of the of $CO_2$ from the rest of flue gases. This review covers the issues related to oxygen carrier materials. The modeling works are reviewed and different aspects of modeling are considered, as well. The main drawbacks and future research and prospects are remarked.

• Ocean and Polar Research
• /
• v.23 no.4
• /
• pp.433-440
• /
• 2001

Marine organisms in Antarctica live in an environment which exhibits variability in physical processes over a wide range of temporal scales, from seconds to millennia. This time scale tends to be correlated with the spatial scale over which a given process operates, though this relationship is influenced by biology. The way organisms respond to variability in the physical environment depends on the time-scale of that variability in relation to life-span. Short-term variations are perceived largely as noise and probably have little direct impact on ecology. Of much greater importance to organisms in Antarctica are seasonal and decadal variations. Although seasonality has long been recognised as a key feature of polar environments, the realization that decadal scale variability is important is relatively recent. Long-term change has always been a feature of polar environments and may be a key factor in the evolution of the communities we see today.