Search

The Semantic Web is an extension of the current Web where information is represented in a machine processable way. It is not separate from the current Web and one of the confusions that novice users might have is where the Semantic Web is. In fact, users can easily encounter RDF documents that are components of the Semantic Web while they navigate among Web pages. In addition, the number of RDF documents on the Web is ever-increasing and a lot of educational materials in RDF format become available on the Web. In this paper, we propose a simple Semantic Web browser by which non-expert users such as secondary school students who do not know technical details about the Semantic Web can browse through HTML documents and RDF documents.

Today, startups are achieving innovation differently from traditional companies based on quick application of new technologies, promptness in decision-making, and active risk-taking. In this background, the startup innovation ecosystem (SIE) is defined as a system of innovation actors and influencing factors and their relationship, affecting innovation-based startup activities and their performance. SIE is distinct from the traditional national innovation system (NIS) and has an impact on NIS and government policy, co-evolving in the time. This study investigated how the Korean government, which is experiencing the R&D paradox of high R&D investment but low productivity, seeks to change the NIS by developing the SIE. According to our analytical framework of the SIE, Korea's SIE is analysed in terms of startups, technology/knowledge, training/human capital, finance, infrastructure, and globalisation. In particular, the evolutionary process of startups-related policies is explained with several specific examples of policy programmes. It is found that Korea's SIE has achieved unique development, with the government's active supporting policy for startups, and has produced a big positive impact on Korea's NIS. [ABSTRACT FROM AUTHOR]

Hematomas caused by the rupture of a pseudoaneurysm in the middle meningeal artery (MMA) after trauma usually present as epidural hematomas. Intracerebral hemorrhage (ICH) is extremely rare. We reviewed ICH due to the rupture of MMA pseudoaneurysms. We found that in cases of acute ICH, a pseudoaneurysm was attached to the outer surface of the dura mater and associated with dura tear. In patients with acute ICH, the intraoperative rupture of a pseudoaneurysm developed just after bone flap removal. In cases of delayed ICH, pseudoaneurysms adhered to the inner surface of the dura mater. In patients with delayed ICH, the intraoperative rupture of a pseudoaneurysm developed during dura opening and hematoma removal. In situations of dura tear after trauma, the rupture of pseudoaneurysms might lead to ICH via a dura tear. Pseudoaneurysms that develop in the MMA after trauma may exert pressure and result in the thinning of the dura mater. In this case, pseudoaneurysms will adhere to the inner surface of the dura mater after several days or weeks. ICH might develop through both acute and delayed mechanisms following the development of pseudoaneurysms in the MMA. Clinicians should pay attention to the timing of such ruptures during operations for both acute and delayed ICH. [ABSTRACT FROM AUTHOR]

To better understand environmental electromagnetic wave exposure during the use of digital textbooks by elementary school students, we measured numeric values of the electromagnetic fields produced by tablet personal computers (TPCs). Specifically, we examined the distribution of the electromagnetic waves for various students' seating positions in an elementary school that uses digital textbooks. Electric and magnetic fields from TPCs were measured using the HI-3603 Visual Display Terminal/ Very Low Frequency (VDT/VLF) radiation measurement system. Electromagnetic field values from TPCs measured at a student's seat and at a teacher's computer were deemed not harmful to health. However, electromagnetic field values varied based on the distance between students, other electronic devices such as a desktop computers, and student posture while using a TPC. Based on these results, it is necessary to guide students to observe proper posture and to arrange seats at an appropriate distance in the classroom.

South Korea's successful reforestation efforts over the past 50 years have led to abundant forest resources. However, intensive reforestation during the 1970s and 1980s skewed the forests' age distribution towards forest stands aged 30 years or older, which results in an unbalanced distribution of age-class, requiring redistribution with harvest and effective regeneration plans to produce a sustained yield of timber as well as long term ecological benefits. During this conversion process, variations in timber production can occur, causing economic and ecological risks if excessive. To prevent these likely risks, permissible levels of increase and decrease in timber production can be restricted in the planning phase. In determining the appropriate variation rate in timber production, it is necessary to understand the impacts of variation in timber production on forest management. This study performed a sensitivity analysis to evaluate the economic and ecological impacts of constraining the period-to-period variation in timber production. A multi-objective linear programming (MOLP) forest management planning model was utilized to study forests in Mt. Gari, South Korea. Nine management alternatives were set with different levels of variation rate in timber production and further constraints. The total volume and net present value (NPV) of timber production, carbon storage, and water storage were analyzed for each alternative. As timber production variation rates decreased, the amount of timber production increased and forest carbon storage decreased; furthermore, NPV diminished as variation constraints strengthened. These differences were mainly caused by selection of regeneration species according to the constraint on variation in timber production. If the variation rate was strictly restricted, the area of timber species with short rotation age increased during conversion period, in order to reduce the gap of timber production between periods. At the latter part of planning horizon, the area of broad-leaved trees was enlarged as the burden of adjusting age-class structure reduced. The appropriate variation rate in timber production was determined to be 30%, based on considerations regarding the economic and ecological impact of the variation on the forest. [ABSTRACT FROM AUTHOR]

In order to estimate the crack depth in concrete using time-of-flight, finite element analysis and experiments were performed on non-cracked concrete blocks and 45 mm and 70 mm vertical cracks. As a result of measuring the time-of-flight change by changing the positions of the transmitter and receiver, it was confirmed that the finite element analysis results agreed with the experimental results, and high accuracy was confirmed by various formulas for calculating the depth of defects using the obtained experimental measurements for comparison. In addition to the verification of the simulation and experimental theory, research was conducted through actual field cases, and methodologies for crack detection and depth evaluation for concrete structures were presented, and furthermore, the expected effects of improving the soundness and safety of structures were shown. [ABSTRACT FROM AUTHOR]

This study examined the efficacy of a culturally responsive housing with services model for Asian-American older adults and persons with developmental disabilities separately, and with both for an interaction effect. Study participants, including 278 Whites and 75 Asian Americans, lived in 10 properties of public housing with services in Portland, OR. All Asian-American participants (except four) were immigrants from China, Korea, and Vietnam, and were well connected through community-based health and social services that were delivered onsite and at a nearby center by staff members who were also immigrants from these three countries. Asian-American participants were older, very poor, with limited English proficiency, but, reported stronger family connection and satisfaction with the living environment, which reflected in lower health care needs and utilization, and better quality of life. Participants with developmental disabilities comprised 27 individuals who reported greater health care needs, service utilization, and food insecurity. Asian-American participants with developmental disabilities reported stronger family connections. Regression analyses found level of health care needs was consistently the strongest predictor, followed by food insecurity and family connection, in predicting perceived quality of life. Findings offer insight into a culturally responsive housing services model where minority culture is no longer a risk factor and limited English language proficiency is no longer a cause of isolation. [ABSTRACT FROM AUTHOR]

We evaluated the long-term outcomes of coronary artery bypass grafting (CABG) according to β-blocker therapy using landmark analysis. Although β-blockers have been shown to improve outcomes for ischemic heart disease, the long-term effects and optimal treatment duration of use after CABG remain unknown. From January 2001 to December 2014, 5382 CABG patients were stratified into 2 groups according to β-blocker therapy at discharge (β-blocker group: 3677 [68.3%], no β-blocker group: 1705 [31.7%]). The primary outcome was all-cause death during 48 months of follow-up. Using propensity score-matched analysis, β-blocker therapy was associated with all-cause death during the 48-month follow-up (hazard ratio [HR], 0.62; 95% confidence interval [CI], 0.41-0.95; P =.03). The landmark analysis demonstrated that the effect of β-blockers on all-cause death was particularly significant within the first 12 months of therapy (HR, 0.37; 95% CI, 0.19-0.80; P =.01) but not after 12 months (HR, 0.92; 95% CI, 0.56-1.53; P =.77). The benefits of postdischarge β-blockers may be limited to 1 year after CABG, but further studies are required to confirm this finding. [ABSTRACT FROM AUTHOR]

This article a new multiple-band single-pole N-throw (SPNT) switch topology suitable for mm-wave applications. Compared to a conventional shunt-type SPNT switch, the proposed SPNT operates in the multiple frequency bands by adopting a variable transmission-line (T-line) structure. The variable T-line (VTL) structure consists of multiple sections of T-line and multiple shunt switches. Therefore, it realizes a variable quarter-wave line at different frequencies depending on the ON–OFF configuration of the multiple shunt switches. To validate the proposed topology, two versions of a triple-band SP3T switch operating at 20, 30, and 40 GHz are demonstrated in a 65-nm bulk CMOS technology. The first version (SW1) employs a minimum number of shunt switches in the VTL structure, thus minimizing the insertion loss. The second version (SW2) includes extra shunt switches in the VTL, thus improving the isolation. The measurement shows that SW1 exhibits insertion loss of 3, 3.4, and 3.6 dB at 20, 30, and 40 GHz, respectively. The isolations are 22.8 or 20 dB at 20 GHz, 18.5 or 21.5 dB at 30 GHz, and 19.7 or 23.5 dB at 40 GHz, depending on the operation mode. On the other hand, SW2 shows improved isolation of 36.2 or 45 dB at 20 GHz, 19.6 or 42.8 dB at 30 GHz, and 22.7 or 38.6 dB at 40 GHz. The insertion losses are 3.6, 3.8, and 3.9 dB at 20, 30, and 40 GHz, respectively. [ABSTRACT FROM AUTHOR]

An analysis and design of distributed frequency doublers is presented at millimeter-wave (mm-wave) frequencies, including the $D$ -, $G$ -, and $H$ -bands. The phase condition required for coherent output summation in the distributed multipliers is analyzed to maximize the output power and bandwidth. Based on the analysis, two mm-wave distributed frequency doublers are designed and experimentally demonstrated. The first doubler combines three unit cells in a distributed manner, while the insertion phase is equalized between the input and output artificial transmission lines (T-lines). A differential quasi-cascode structure is proposed for each unit cell, which enables the bandwidth extension and chip-size reduction. The differential doubler exhibits a measured peak output power and a conversion gain of 3.5 dBm and −2.5 dB, respectively, at the output frequency of 165 GHz. At 276 GHz, the output power and conversion gain are 1.6 dBm and −6.2 dB, respectively. The doubler maintains high output power above −5 dBm from 108 to 316 GHz, which covers almost the entire $D$ -, $G$ -, and $H$ -bands. The second doubler combines five single-ended cascode unit cells to improve the output power and conversion gain. A bandpass filter is employed at the output T-line for spurious signal suppression. The single-ended doubler shows a measured peak output and conversion gain of 5.5 dBm and 0.3 dB, respectively, at 240 GHz. The bandwidth for −5-dBm output is from 220 to 290 GHz. Both doublers occupy a small chip area of 0.23 and 0.27 mm2, respectively, including all probing pads. [ABSTRACT FROM AUTHOR]

Under the influence of the common goals of Education For All (EFA), Millennium Development Goals (MDGs) and Sustainable Development Goals (SDGs) in the international development realm, many countries around the world have reached a great level of development through continuous improvement in education since 2000. Meanwhile, Morocco could be one of the developing countries that struggle to resolve many problems resulting from having a weak educational system, which has been considered as one of the main obstacles to the country's economic growth. The purpose of this article is to analyse the gender gap in access to primary education in rural areas of Morocco, focusing on primary school girls. Based on the investigation on the major obstacles, we carried out descriptive statistics with selected variables such as the adjusted net enrolment rate, the cumulative drop-out rate to the last grade, the gross intake ration (graduation ratio) to the last grade, and Gender Parity Index (GPI). In addition, we conducted a few private interviews via Skype with local stakeholders to underpin our research and to reflect personal ideas on the Moroccan educational system from their own perspective. Lastly, we suggested applicable solutions against those barriers from the perspective of education ODA. [ABSTRACT FROM AUTHOR]

Slag foaming directly affects the productivity and quality of steel during the electric arc furnace (EAF) process. Therefore, the slag foaming height needs to be monitored in real-time. However, direct measurement of the slag foaming height is difficult to achieve because the inside of the EAF consists of harsh environments, i.e., high temperature and the presence of gas and dust. A stepwise regression model of the slag foaming height was created using sensor data from the EAF. A total of 272 operational data sets from the EAF process were used to develop and validate the regression model. This data came from 140ton DC-EAF of Dongkuk Steel in Pohang, Korea. We randomly selected 80% of the data for developing the regression model; the remaining 20% of data were used for model validation. The model was validated using the validation benchmark coefficient of determination (R2) and correlation coefficients. As a result, the important variables of slag foaming were statistically selected a priori. Using the regression model, the slag foaming height can be predicted without additional sensors. Based on the developed model, the effects of oxygen injection and carbon injection on the slag foaming height of EAF were predicted and are discussed herein. [ABSTRACT FROM AUTHOR]

We present a novel technique for 3D point cloud simplification — the so-called fractal bubble algorithm — to minimize the computational time and overall storage space. The proposed fractal bubble algorithm generates 2D elastic bubbles and copies of themselves through 2D data sets representing planar geometric contours. Each of the bubbles, as it grows, is made to select a single point of its first contact, and all the selected points become the simplified set of points. The fractal bubble algorithm is repeatedly applied to the simplification of planar slices of general 3D point clouds corresponding to 3D geometric objects, leading to the global simplification of 3D point clouds. The benefits of the algorithm are: first the algorithm is computationally light and memory efficient, second it is simple to implement and inherently allows the organized selection of the points of contact and finally it enables us to simplify the point cloud data through a multi-scale fashion by varying a set of user-controlled algorithm parameters. Numerical results verify the effectiveness of the proposed algorithm. [ABSTRACT FROM AUTHOR]

This Letter presents a single-pole single-throw (SPST) switch for high-power applications in the mm-wave frequency band. A stacked-FET structure is adopted in the shunt switching cell for reducing the insertion loss and improving the linearity of the switch. To enhance the isolation, the parasitic inductance of the stacked-FET structure is resonated out by connecting a series capacitor. The number of stacked FETs in each shunt cell and the number of the shunt cells are optimised considering the trade-off among the insertion loss, isolation, and linearity. The SPST switch is fabricated in a 70-nm GaAs m-HEMT process. The measurement shows that the insertion loss is <1.1 dB, and the isolation is >25 dB over the frequency from 59 to 77 GHz. Both the insertion loss and isolation are not compressed at all until the input power reaches 19.5 dBm at 75 GHz. [ABSTRACT FROM AUTHOR]

This paper presents a wideband vector-sum phase shifter (VSPS) that operates over the entire WR-3 band (220–320 GHz). Compared to conventional VSPSs with double Gilbert cells, the proposed phase shifter employs a single Gilbert-cell structure for vector modulation. This reduces the output current combining ratio from 8:2 to 4:2, and boosts the impedance at the combining node, thus facilitating wideband output matching at upper millimeter-wave and terahertz bands. The simplified structure leads to a reduction in dc power consumption and chip area without sacrificing the 360^\circ phase-shifting property. Lossy matching is applied at the Gilbert-cell output to further increase bandwidth and stability at the expense of relatively high loss. The phase shifter is implemented using a 250-nm InP DHBT technology that provides f T and f \max exceeding 370 and 650 GHz, respectively. The measurements exhibit a wideband phase shift with continuous 360^\circ coverage and average insertion loss ranging from 11.8 to 15.6 dB for the entire WR-3 band. The root mean square amplitude and phase error among different phase states are less than 1.2 dB and 10.2^\circ, respectively. The input-referred 1-dB compression is measured at \0.7 dBm on average. The dc power consumption is 21.8–42.0 mW at different phase states. [ABSTRACT FROM PUBLISHER]

A high-efficiency rectenna is designed at 2.4 GHz. In general, a rectenna consists of an antenna, a band-pass filter, a rectifying diode, and a low-pass filter. In this article, to increase transmission efficiency, a high-directional antenna is developed using partially reflective surfaces. In addition, the harmonic rejecting band-pass filter is designed to suppress the second and third harmonic signal from the nonlinear diode, resulting in high conversion efficiency. It is experimentally demonstrated that the proposed rectenna achieves an RF to DC conversion efficiency of 72.17% when the received RF power is 63.09 mW at 2.4 GHz. [ABSTRACT FROM AUTHOR]

A compact and high efficient magnetic coupled resonator that uses additional parallel capacitors is presented. The proposed resonators are used as a transmitter (TX) and receiver (RX) for a magnetic coupled wireless power transmission. Compared with a conventional magnetic coupled resonator, the resonator's size is effectively decreased and the efficiency is increased by the additional capacitor at long distances. Interestingly, the proposed wireless power transmission system shows increased efficiency even when the axis between the TX and RX is misaligned, in contrast to with the conventional one. The proposed resonator has 88% maximum efficiency at a distance of 45 cm, and maintains 80% efficiency up to 25 cm offset. [ABSTRACT FROM AUTHOR]

This paper presents a CMOS wideband miniature balun operating over the full K- and Ka-bands. The balun is based on a single spiral coupled structure where two symmetric spiral lines are stacked vertically (i.e. broadside-coupled) in an antipodal manner. The proposed structure provides ultra-wideband balun performance while occupying a minimal chip area compared with conventional spiral baluns. In order to offset residual inductance of the spirals, a compensation capacitor is shunted at the end of an unbalanced input line, which further improves the bandwidth. The proposed balun is implemented in a bulk 0.13-μm CMOS process. The measured insertion loss is less than 6.5 dB from 14 to 40 GHz. The amplitude and phase imbalances are less than 1 dB and 10°, respectively, over the entire bandwidth. The balun occupies an area of only 0.0095 mm², which, to the authors' knowledge, is significantly smaller than any previously reported CMOS baluns at similar frequency bands. [ABSTRACT FROM AUTHOR]

This study proposes a new corporate transparency index comprising four sub-indices: financial, governance, operational, and social transparency. Using our index, we examine the effects of corporate transparency on firm value and the profitability of 162 Korean venture firms. Results show that corporate transparency is positively associated with firm profitability. Financial transparency is positively related to firm profitability and negatively associated with firm value. Firms with a greater level of governance transparency have a higher firm value and a lower return on assets. Operational transparency is negatively related to firm value. Social transparency is positively associated with firm value and profit. [ABSTRACT FROM AUTHOR]