Solid-state fiber dye-sensitized solar cells(SS-FDSSCs) have been the subject of intensive attention and development in recent years. Although this field is only in its infancy, metal–organic frameworks(MOFs) are one...Solid-state fiber dye-sensitized solar cells(SS-FDSSCs) have been the subject of intensive attention and development in recent years. Although this field is only in its infancy, metal–organic frameworks(MOFs) are one such material that has been utilized to further improve the power conversion efficiency of solar cells. In this study, MOF-integrated DSSCs were shown to have potential in the development of solar cell devices with efficiency comparable to or better than that of conventional solar cells. The power conversion efficiency(PCE) of SS-FDSSCs was improved by embedding MOF-801 into a mesoporous-TiO_(2)(mp-TiO_(2)) layer, which was used as a photoanode in SS-FDSSCs, which are inherently flexible. The PCE of the MOF-integrated SS-FDSSCs was 6.50%, which is comparable to that of the reference devices(4.19%).The MOF-801 enhanced SS-FDSSCs decreased the series resistance(R_(s)) value, resulting in effective electron extraction with improved short-circuit current density(J_(SC)), while also increasing the shunt resistance(R_(sh)) value to prevent the recombination of photo-induced electrons. The result is an improved fill factor and, consequently, a higher value for the PCE.展开更多
Since a sensor node handles wireless communication in data transmission and reception and is installed in poor environment, it is easily exposed to certain attacks such as data transformation and sniffing. Therefore, ...Since a sensor node handles wireless communication in data transmission and reception and is installed in poor environment, it is easily exposed to certain attacks such as data transformation and sniffing. Therefore, it is necessary to verify data integrity to properly respond to an adversary's ill-intentioned data modification. In sensor network environment, the data integrity verification method verifies the final data only, requesting multiple communications. An energy-efficient private information retrieval(PIR)-based data integrity verification method is proposed. Because the proposed method verifies the integrity of data between parent and child nodes, it is more efficient than the existing method which verifies data integrity after receiving data from the entire network or in a cluster. Since the number of messages for verification is reduced, in addition, energy could be used more efficiently. Lastly, the excellence of the proposed method is verified through performance evaluation.展开更多
The technique of region of interest-based positron emission tomography is limited by its poor reli-ability and relatively few examined brain regions. In the present study, we compared brain metabo-lism assessed using ...The technique of region of interest-based positron emission tomography is limited by its poor reli-ability and relatively few examined brain regions. In the present study, we compared brain metabo-lism assessed using fluorine-18-fluorodeoxyglucose positron emission tomography between 14 at-tention-deficit hyperactivity disorder （ADHD） patients and 15 normal controls with scoliosis at resting state by statistical parametric mapping. Glucose metabolism was decreased in the left parahippo-campal gyrus, left hippocampus, left anterior cingulate gyrus, right anterior and posterior lobes of the cerebellum, left superior temporal gyrus, left insula, left medial and middle frontal gyri, right medial frontal gyrus, and left basal ganglia （putamen, amygdala, and caudate nucleus） in children with ADHD. These data suggest that children with ADHD exhibit hypometabolism in various brain regions compared to controls, indicating that ADHD symptoms are unlikely the result of abnormalities in specific areas.展开更多
The performance of an integrated packet voice/data multiplexer using a stop-and-wait(SW)automatic repeat request(ARQ)protocol is discussed.We assume that the input for the data traffic is exponentially distributed in ...The performance of an integrated packet voice/data multiplexer using a stop-and-wait(SW)automatic repeat request(ARQ)protocol is discussed.We assume that the input for the data traffic is exponentially distributed in increments via the Poisson process,with each data packet transmitted within an individual slot time.Another assumption is that there is only a single voice signal,which has a higher priority over the data packet,and whose traffic is given via an on-off Markov process.Whenever the voice signal is active,the output link is used and will be blocked for the data packet.We introduce the concept of buffer occupancy to simplify the analysis,and discover that data multiplexers using the SW ARQ protocol exhibit a behavior of queueing delay and buffering when the interruption signal is given via a Markov process.Simulation results verify the validity of the analytical results.展开更多
基金supported by the Fundamental Research Program(PNK 7350 and PNK 7340)of the Korea Institute of Materials Science(KIMS)the National Research Foundation(NRF)grant funded by the Korean government(MEST)(2021R1A2C2014192)。
文摘Solid-state fiber dye-sensitized solar cells(SS-FDSSCs) have been the subject of intensive attention and development in recent years. Although this field is only in its infancy, metal–organic frameworks(MOFs) are one such material that has been utilized to further improve the power conversion efficiency of solar cells. In this study, MOF-integrated DSSCs were shown to have potential in the development of solar cell devices with efficiency comparable to or better than that of conventional solar cells. The power conversion efficiency(PCE) of SS-FDSSCs was improved by embedding MOF-801 into a mesoporous-TiO_(2)(mp-TiO_(2)) layer, which was used as a photoanode in SS-FDSSCs, which are inherently flexible. The PCE of the MOF-integrated SS-FDSSCs was 6.50%, which is comparable to that of the reference devices(4.19%).The MOF-801 enhanced SS-FDSSCs decreased the series resistance(R_(s)) value, resulting in effective electron extraction with improved short-circuit current density(J_(SC)), while also increasing the shunt resistance(R_(sh)) value to prevent the recombination of photo-induced electrons. The result is an improved fill factor and, consequently, a higher value for the PCE.
基金supported by the Sharing and Diffusion of National R&D Outcome funded by the Korea Institute of Science and Technology Information
文摘Since a sensor node handles wireless communication in data transmission and reception and is installed in poor environment, it is easily exposed to certain attacks such as data transformation and sniffing. Therefore, it is necessary to verify data integrity to properly respond to an adversary's ill-intentioned data modification. In sensor network environment, the data integrity verification method verifies the final data only, requesting multiple communications. An energy-efficient private information retrieval(PIR)-based data integrity verification method is proposed. Because the proposed method verifies the integrity of data between parent and child nodes, it is more efficient than the existing method which verifies data integrity after receiving data from the entire network or in a cluster. Since the number of messages for verification is reduced, in addition, energy could be used more efficiently. Lastly, the excellence of the proposed method is verified through performance evaluation.
文摘The technique of region of interest-based positron emission tomography is limited by its poor reli-ability and relatively few examined brain regions. In the present study, we compared brain metabo-lism assessed using fluorine-18-fluorodeoxyglucose positron emission tomography between 14 at-tention-deficit hyperactivity disorder （ADHD） patients and 15 normal controls with scoliosis at resting state by statistical parametric mapping. Glucose metabolism was decreased in the left parahippo-campal gyrus, left hippocampus, left anterior cingulate gyrus, right anterior and posterior lobes of the cerebellum, left superior temporal gyrus, left insula, left medial and middle frontal gyri, right medial frontal gyrus, and left basal ganglia （putamen, amygdala, and caudate nucleus） in children with ADHD. These data suggest that children with ADHD exhibit hypometabolism in various brain regions compared to controls, indicating that ADHD symptoms are unlikely the result of abnormalities in specific areas.
文摘The performance of an integrated packet voice/data multiplexer using a stop-and-wait(SW)automatic repeat request(ARQ)protocol is discussed.We assume that the input for the data traffic is exponentially distributed in increments via the Poisson process,with each data packet transmitted within an individual slot time.Another assumption is that there is only a single voice signal,which has a higher priority over the data packet,and whose traffic is given via an on-off Markov process.Whenever the voice signal is active,the output link is used and will be blocked for the data packet.We introduce the concept of buffer occupancy to simplify the analysis,and discover that data multiplexers using the SW ARQ protocol exhibit a behavior of queueing delay and buffering when the interruption signal is given via a Markov process.Simulation results verify the validity of the analytical results.
