• Environmental and Resource Economics Review
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• v.26 no.1
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• pp.57-83
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• 2017

The Japanese government's attempts to reduce fine particles (PM2.5) emission pollution in Japan have been largely ineffective. This is because PM2.5 in Japan originated from various sources including around half from oversea countries such as China. This prompts the Japanese government to start a new initiative to reduce PM2.5 at its origin by transferring local knowledge on air pollution reduction measures and technologies to China and working closely with the Chinese government. To promote further reduction in PM2.5, bilateral corporation between Japan and China should be extended to include Korea. It is recommended that an international convention should be in place to deal with transboundary air pollutants in East Asia. A successful East Asia corporation to reduce PM2.5 will not only contribute to clean air but also to future sustainable low carbon society in this region.

• Journal of the Ergonomics Society of Korea
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• v.26 no.4
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• pp.153-160
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• 2007

Due to the high occurrence rate of musculoskeletal disorders(MSDs), many Korean companies adopted various assessment tools to evaluate workers' musculoskeletal stress. Using the results of this evaluation, tasks were selected for improvements. However, there are still many workers who complained of musculoskeletal stress of their tasks. Their tasks usually consist of repetitive activities and a short rest cycle. This prompts a concern of reliability of the evaluation tools and especially RULA. Thus in this study, OCRA(The Occupational Repetitive Action tool) was used to check whether RULA(Rapid Upper Limb Assessment) evaluates workers' musculoskeletal stress reasonably well since OCRA has been known to be a good evaluation tool for repetitive tasks and tasks with short recovery periods. The evaluation was conducted on 142 tasks. It was found that 65 tasks showed higher action levels by OCRA than by RULA. However, 13 tasks showed the reversed result and 64 tasks showed the same level regardless of the evaluation tool. It was concluded that either RULA or OCRA alone cannot evaluate all types of tasks very well. It is suggested that OCRA needs to be used with RULA together for the evaluations of musculoskeletal stress at workplaces where repetitive activities and short recovery periods exist.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.10
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• pp.5883-5890
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• 2013

Previously, we demonstrated overexpression of semaphorin4D (SEMA4D, CD100) to be closely related to tumor angiogenesis in epithelial ovarian cancers (EOCs). However, the function and expression of SEMA4D in the EOC microenvironment has yet to be clarified in detail. In this study, we confirmed that overexpression of SEMA4D in primary tumors and ascites was related to low differentiation, platinum resistance and a refractory status (P<0.05), while high M2 macrophage count and percentage were evident in EOC patients with advanced FIGO stage and platinum resistance (P<0.05), using immunohistochemistry, enzyme-linked immunosorbent assay (ELISA), and fluorescence-activated cell sorting (FACS), respectively. The data showed correlations of SEMA4D expression and M2 macrophage counts in primary tumors and M2 macrophage percentage in ascites (r=0.281 and 0.355, each P<0.05). In the Cox proportional hazard mode, SEMA4D expression was an independent indicator of overall survival (OS) and progression-free survival (PFS) for EOC patients. Furthermore, higher expression of SEMA4D in ovarian cancer cell lines (SKOV3, A2780, and SW626) and their supernatants were found than that in a human primary cultured ovarian cell and its supernatant by reversed transcript PCR (RT-PCR), Western blotting and ELISA, respectively. Interestingly, peripheral blood monocytes (MOs) tended towards the M2-polarized macrophage phenotype ($CD163^{high}$) in vitro after human recombined soluble SEMA4D protein stimulation. These findings suggest that SEMA4D might possibly serve as a reliable tool for early and accurate prediction of EOC poor prognosis and could playan important role in promoting tumor dissemination and metastasis in the EOC microenvironment. Thus SEMA4D and its role in macrophage polarization in EOC warrants further study.

• School Mathematics
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• v.12 no.4
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• pp.455-471
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• 2010

Understanding of randomness is essential for learning and teaching of probability and statistics. Understanding of randomness prompts to understand natural and social phenomena from the point of view of mathematics, and plays a role of base in understanding of judgments based on rational interpretation on these phenomena. This study examined whether pre-service teachers recognize this, and they understand randomness included in various contexts. According to results, they did not have a understanding of randomness in the context related to measuring, while they grasped randomness in simple and joint events. This implies that they lack the understanding of variability which is essential in the context of measuring. This study, therefore, suggests that the settings of measuring should be introduced into probability and statistics education, especially that data from measuring should be analyzed focusing on the variability in the data set.

• Smart Structures and Systems
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• v.17 no.6
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• pp.917-933
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• 2016

In a prestressed concrete bridge, the magnitude of the prestress force (PF) decreases with time. This unexpected loss can cause failure of a bridge which makes prestress force identification (PFI) critical to evaluate bridge safety. However, it has been difficult to identify the PF non-destructively. Although some research has shown the feasibility of vibration based methods in PFI, the requirement of having a determinate exciting force in these methods hinders applications onto in-service bridges. Ideally, it will be efficient if the normal traffic could be treated as an excitation, but the load caused by vehicles is difficult to measure. Hence it prompts the need to investigate whether PF and moving load could be identified together. This paper presents a synergic identification method to determine PF and moving load applied on a simply supported prestressed concrete beam via the dynamic responses caused by this unknown moving load. This method consists of three parts: (i) the PF is transformed into an external pseudo-load localized in each beam element via virtual distortion method (VDM); (ii) then these pseudo-loads are identified simultaneously with the moving load via Duhamel Integral; (iii) the time consuming problem during the inversion of Duhamel Integral is overcome by the load-shape function (LSF). The method is examined against different cases of PFs, vehicle speeds and noise levels by means of simulations. Results show that this method attains a good degree of accuracy and efficiency, as well as robustness to noise.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.38 no.8
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• pp.19-29
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• 2001

The recent explosion in the Internet applications, Internet. host number and the traffic in the IP backbone network is posing new challenges for transport network. This requires a high-speed IP backbone network that has a substantially higher bandwidth than the one offered by current networks, which prompts the development of all-optical network. To obtain optical network utilization gains, we need a software which establishs logical topology to make possible the efficient use or physical topology, and control the optical network in combination with the IP layer routing protocols. Finally, the logical topology is required higher efficient than physical topology. For this an efficient algorithm for the routing and wavelength assignment(RWA) in the WDM all-optical network is necessary. In this paper, two kinds of heuristic algorithms to establish logical topology for WDM networks and arc applied to the design of logical topology of domestic backbone network. These algorithms are found to work quite well and they arc compared with each other in terms of blocking rate, etc.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.18 no.6
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• pp.243-250
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• 2018

This paper designs and implements a smart care system for the senior citizen who lives alone. Recently, as the level of living has increased due to the rapid improvement of medicine, living standard and environment, the proportion of the elderly population is increasing. In addition, the proportion of the elderly living alone, which is increasing with the aging society, suggests that the provision of services such as the elder care system and emergency notification is becoming an important issue. However, since the existing emergency notification technology analyzes fixed CCTV images, it is difficult to monitor in the blind spot of CCTV and to move to a place where the camera is not installed. There is a problem that it can not be performed. Therefore, in this paper, we design and develop a smart care system that utilizes robot and object tracking technology that can move in real time to overcome these shortcomings. This enables real-time monitoring regardless of the location, and prompts for assistance in case of an emergency, so that it can provide convenience to cares and assistants.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.17 no.4
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• pp.131-136
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• 2007

Ad hoc networks enable efficient resource aggregation in decentralized manner, and are inherently scalable and fault-tolerant since they do not depend on any centralized authority. However, lack of a centralized authority prompts many security-related challenges. Moreover, the dynamic topology change in which network nodes frequently join and leave adds a further complication in designing effective and efficient security mechanism. Security services for ad hoc networks need to be provided in a scalable and fault-tolerant manner while allowing for membership change of network nodes. In this paper, we investigate distributed certification mechanisms using a threshold cryptography in a way that the functions of a CA(Certification Authority) are distributed into the network nodes themselves and certain number of nodes jointly issue public key certificates to future joining nodes. In the process, we summarize one interesting report [5] in which the recently proposed RSA-based ad hoc signature scheme, called URSA, contains unfortunate yet serious security flaws. We then propose new scheme by fixing their security flaws.

• Computers and Concrete
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• v.29 no.4
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• pp.263-278
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• 2022

Limestone calcined clay cement (LC³) is a low carbon alternative to conventional cement. Literature shows that using limestone and calcined clay in LC³ increases the thermal degradation of LC³ pastes and can increase the magnitude of fire risk in LC³ concrete structures. Higher thermal degradation of LC³ paste prompts this study toward understanding the fire performance of LC³ concrete and the associated magnitude of fire risk. For fire performance, concrete prepared using ordinary Portland cement (OPC), pozzolanic Portland cement (PPC) and LC³ were exposed to 16 scenarios of different elevated temperatures (400℃, 600℃, 800℃, and 1000℃) for different durations (0.5 h, 1 h, 2 h, and 4 h). After exposure to elevated temperatures, mass loss, residual ultrasonic pulse velocity (rUPV) and residual compressive strength (rCS) were measured as the residual properties of concrete. XRD (X-ray diffraction), TGA (thermogravimetric analysis) and three-factor ANOVA (analysis of variance) are also used to compare the fire performance of LC³ with OPC and PPC. Monte Carlo simulation has been used to assess the magnitude of fire risk in LC³ structures and devise recommendations for the robust application of LC³. Results show that LC³ concrete has weaker fire performance, with average rCS being 11.06% and 1.73% lower than OPC and PPC concrete. Analysis of 106 fire scenarios, in Indian context, shows lower rCS and higher failure probability for LC³ (95.05%, 2.22%) than OPC (98.16%, 0.22%) and PPC (96.48%, 1.14%). For robust application, either LC³ can be restricted to residential and educational structures (failure probability <0.5%), or LC³ can have reserve strength (factor of safety >1.08).

• Applied Chemistry for Engineering
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• v.34 no.5
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• pp.556-565
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• 2023

Fast industrial and agricultural expansion result in the production of heavy metal ions (HMIs). These are exceedingly hazardous to both humans and the environment, and the necessity to eliminate them from aqueous systems prompts the development of novel materials. In the present study, a UIO-66 (COOH)₂ metal-organic framework (MOF) containing free carboxylic acid groups was post-synthetically modified with L-glutamic acid via the solid-solid reaction route. Pristine and glutamic acid-treated MOF materials were characterized in detail using several physicochemical techniques. Single-ion batch adsorption studies of Pb(II) and Hg(II) ions were carried out using pristine as well as amino acid-modified MOFs. We further examined parameters that influence removal efficiency, such as the initial concentration and contact time. The bare MOF had a higher ion adsorption capacity for Pb(II) (261.87 mg/g) than for Hg(II) ions (10.54 mg/g) at an initial concentration of 150 ppm. In contrast, an increased Hg(II) ion adsorption capacity was observed for the glutamic acid-modified MOF (80.6 mg/g) as compared to the bare MOF. The Hg(II) ion adsorption capacity increased by almost 87% after modification with glutamic acid. Fitting results of isotherm and kinetic data models indicated that the adsorption of Pb(II) on both pristine and glutamic acid-modified MOFs was due to surface complexation of Pb(II) ions with available -COOH groups (pyromellitic acid). Adsorption of Hg(II) on the glutamic acid-modified MOF was attributed to chelation, in which glutamic acid grafted onto the surface of the MOF formed chelates with Hg(II) ions.