Sil‐Gu Mun  Eun‐Gu Lee  Jie Hyun Lee  Heuk Park  Sae‐Kyoung Kang  Han Hyub Lee  Kwangok Kim  Kyeong‐Hwan Doo  Hyunjae Lee  Hwan Seok Chung  Jong Hyun Lee  Sangsoo Lee  Jyung Chan Lee 《ETRI Journal》2016,38(1):9-17

We demonstrate a time‐ and wavelength‐division multiplexed passive optical network system employing a vertical‐cavity surface‐emitting laser array–based optical line terminal transceiver and a tunable bidirectional optical subassembly–based optical network terminal transceiver. A packet error–free operation is achieved after a 40 km single‐mode fiber bidirectional transmission. We also discuss an arrayed waveguide grating, a photo detector array based on complementary metal–oxide–semiconductor photonics technologies, and low‐cost key devices for deployment in access networks.  相似文献   

    

Jin Ah Kang  Mikyong Han  Jong‐Hyun Jang  Hong Kook Kim 《ETRI Journal》2016,38(6):1064-1073

An adaptive speech streaming method to improve the perceived speech quality of a software‐based multipoint control unit (SW‐based MCU) over IP networks is proposed. First, the proposed method predicts whether the speech packet to be transmitted is lost. To this end, the proposed method learns the pattern of packet losses in the IP network, and then predicts the loss of the packet to be transmitted over that IP network. The proposed method classifies the speech signal into different classes of silence, unvoiced, speech onset, or voiced frame. Based on the results of packet loss prediction and speech classification, the proposed method determines the proper amount and bitrate of redundant speech data (RSD) that are sent with primary speech data (PSD) in order to assist the speech decoder to restore the speech signals of lost packets. Specifically, when a packet is predicted to be lost, the amount and bitrate of the RSD must be increased through a reduction in the bitrate of the PSD. The effectiveness of the proposed method for learning the packet loss pattern and assigning a different speech coding rate is then demonstrated using a support vector machine and adaptive multirate‐narrowband, respectively. The results show that as compared with conventional methods that restore lost speech signals, the proposed method remarkably improves the perceived speech quality of an SW‐based MCU under various packet loss conditions in an IP network.  相似文献   

    

Ki Su Kim  Hyemin Kim  Yunji Park  Won Ho Kong  Seung Woo Lee  Sheldon J. J. Kwok  Sei Kwang Hahn  Seok Hyun Yun 《Advanced functional materials》2016,26(15):2512-2522

Vaccines are commonly administered by injection using needles. Although transdermal microneedles are less invasive promising alternatives, needle‐free topical vaccination without involving physical damage to the natural skin barrier is still sought after as it can further reduce needle‐induced anxiety and is simple to administer. However, this long‐standing goal has been elusive since the intact skin is impermeable to most macromolecules. Here, we show an efficient, noninvasive transdermal vaccination by employing two key innovations: the use of hyaluronan (HA) as vaccine carriers and non‐ablative laser adjuvants. Conjugates of a model vaccine ovalbumin (OVA) and HA—HA–OVA conjugates—induced more effective maturation of dendritic cells in vitro, compared to OVA. Following topical administration in the skin, HA–OVA conjugates penetrated into the epidermis and dermis in murine and porcine skins, as revealed by intravital microscopy and fluorescence assay. Topical administration of HA‐OVA conjugates significantly elevated both humoral and mucosal antibodies, with peak levels at four weeks. An OVA challenge at week eight elicited strong immune‐recall responses. With pretreatment of the skin using non‐ablative fractional laser beams as adjuvant, strong immunization was achieved with much reduced doses of HA–OVA (1 mg kg^–1 OVA). Our results demonstrate the potential of the noninvasive patch‐type transdermal vaccination platform.  相似文献   

    

Ming Yu Jin  Byung‐Man Kim  Hyun Sil Jung  Jun‐Hyeok Park  Deok‐Ho Roh  Dong Guk Nam  Tae‐Hyuk Kwon  Do Hyun Ryu 《Advanced functional materials》2016,26(38):6876-6887

New indoline dyes ( RK‐1 – 4 ) were designed with a planar geometry and high molar extinction coefficient, which provided surprising power conversion efficiency (PCE) with a thin titanium dioxide film in dye‐sensitized solar cells (DSCs). They had a difference in only alkyl chain length. Despite the same molecular structure, the performance of the respective DSCs varied significantly. Investigating the dye adsorption processes and charge transfer kinetics, the alkyl chain length was determined to affect the dye surface coverage as well as the recombination between the injected photoelectrons and the oxidized redox mediators. When applied to the DSCs as a light harvester, RK‐3 with the dodecyl group exhibited the best photocurrent density, consequently achieving the best PCE of 9.1% with a 1.8 μm active and 2.5 μm scattering layer because of the most favorable charge injection. However, when increasing the active layer thickness, overall device performance deteriorated and the charge collection and regeneration played major roles for determining the PCE. Therefore, RK‐2 featuring the highest surface coverage and moderate alkyl chain length obtained the highest PCEs of 8.8% and 7.9% with 3.5 and 5.1 μm active layers, respectively. These results present a promising perspective of organic dye design for thin film DSCs.  相似文献   

    

Joon‐Seok Lee  Kwanghwi Je  Shin‐Hyun Kim 《Advanced functional materials》2016,26(25):4587-4594

Colloidal assemblies develop pronounced structural colors due to the selective diffraction of light. Micropatterns with multiple structural colors are appealing for the use in a variety of photonic applications. Here, a lithographic approach is reported, which provides a high level of control over the size, shape, and color of a micropattern using the anisotropic shrinkage of inverse opals made of a negative photoresist heated to high temperatures. Shrinkage occurs uniformly across the thickness of the film, leading to a blueshift in the structural color while maintaining a high reflectivity across the full visible spectrum. The rate of shrinkage is determined by the annealing temperature and the photoresist crosslinking density. The rate can, therefore, be spatially modulated by applying UV radiation through a photomask to create multicolor micropatterns from single‐colored inverse opals. The lateral dimensions of the micropattern features can be as small as the thickness of the inverse opal.  相似文献   

    

Eun Joo Jeon  Da‐Hye Lee  Yang‐Ji Kim  Jiyun Ahn  Min Jung Kim  Jin‐Taek Hwang  Jinyoung Hur  Mina Kim  Young‐Jin Jang  Tae‐Youl Ha  Dong‐Hyun Seo  Jong Suk Lee  Chang Hwa Jung 《Molecular nutrition & food research》2016,60(12):2587-2601

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Eunjoo Song  Boseok Kang  Hyun Ho Choi  Dong Hun Sin  Hyochan Lee  Wi Hyoung Lee  Kilwon Cho 《Advanced Electronic Materials》2016,2(1)

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Linhan Ouyang  Yizhong Ma  Jai‐Hyun Byun  Jianjun Wang  Yiliu Tu 《Quality and Reliability Engineering International》2016,32(3):783-794

Multi‐response optimization methods rely on empirical process models based on the estimates of model parameters that relate response variables to a set of design variables. However, in determining the optimal conditions for the design variables, model uncertainty is typically neglected, resulting in an unstable optimal solution. This paper proposes a new optimization strategy that takes model uncertainty into account via the prediction region for multiple responses. To avoid obtaining an overly conservative design, the location and dispersion performances are constructed based on the best‐case strategy and the worst‐case strategy of expected loss. We reveal that the traditional loss function and the minimax/maximin strategy are both special cases of the proposed approach. An example is illustrated to present the procedure and the effectiveness of the proposed loss function. The results show that the proposed approach can give reasonable results when both the location and dispersion performances are important issues. Copyright © 2015 John Wiley & Sons, Ltd.  相似文献   

    

Sung Mi Jung  Daniel J. Preston  Hyun Young Jung  Zhengtao Deng  Evelyn N. Wang  Jing Kong 《Advanced materials (Deerfield Beach, Fla.)》2016,28(7):1413-1419

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Hyejung Kim  Sanghan Lee  Hyeon Cho  Junhyeok Kim  Jieun Lee  Suhyeon Park  Se Hun Joo  Su Hwan Kim  Yoon‐Gyo Cho  Hyun‐Kon Song  Sang Kyu Kwak  Jaephil Cho 《Advanced materials (Deerfield Beach, Fla.)》2016,28(23):4705-4712

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