다중혈관 관상동맥 환자에서 y-문합을 이용하여 양쪽 내흉동맥만을 사용한 우회술의 조기 성적

The term photonic crystals appears because of the analogy between electron waves in crystals and the light waves in artificial periodic dielectric structures. During the recent years the investigation of one-, two-and three-dimensional periodic structures has attracted a widespread attention of the world optics community because of great potentiality of such structures in advanced applied optical fields. The interest in periodic structures has been stimulated by the fast development of semiconductor technology that now allows the fabrication of artificial structures, whose period is comparable with the wavelength of light in the visible and infrared ranges.

http://ieeexplore.ieee.org/iel5/6354/16969/00781867.pdf

Photonic crystals

Lots of learning tasks require dealing with graph data which contains rich relation information among elements. Modeling physics systems, learning molecular fingerprints, predicting protein interface, and classifying diseases demand a model to learn from graph inputs. In other domains such as learning from non-structural data like texts and images, reasoning on extracted structures (like the dependency trees of sentences and the scene graphs of images) is an important research topic which also needs graph reasoning models. Graph neural networks (GNNs) are neural models that capture the dependence of graphs via message passing between the nodes of graphs. In recent years, variants of GNNs such as graph convolutional network (GCN), graph attention network (GAT), graph recurrent network (GRN) have demonstrated ground-breaking performances on many deep learning tasks. In this survey, we propose a general design pipeline for GNN models and discuss the variants of each component, systematically categorize the applications, and propose four open problems for future research.

Graph Neural Networks: A Review of Methods and Applications

IEEE Transactions on Pattern Analysis and Machine Intelligence

Child psychiatrists, pediatricians, and other child clinicians need to have a solid understanding of child language development. There are at least four important reasons that make this necessary. First, slowing, arrest, and deviation of language development are highly associated with, and complicate the course of, child psychopathology. Second, language competence plays a crucial role in emotional and mood regulation, evaluation, and therapy. Third, language deficits are the most frequent underpinning of the learning disorders, ubiquitous in our clinical populations. Fourth, clinicians should not confuse the rich linguistic and dialectal diversity of our clinical populations with abnormalities in child language development. The challenge for the clinician becomes, then, how to get immersed in the captivating field of child language acquisition without getting overwhelmed by its conceptual and empirical complexity. In the past 50 years and since the seminal works of Roger Brown, Jerome Bruner, and Catherine Snow, child language researchers (often known as developmental psycholinguists) have produced a remarkable body of knowledge. Linguists such as Chomsky and philosophers such as Grice have strongly influenced the science of child language. One of the major tenets of Chomskian linguistics (known as generative grammar) is that children’s capacity to acquire language is “hardwired” with “universal grammar”—an innate language acquisition device (LAD), a language “instinct”—at its core. This view is in part supported by the assertion that the linguistic input that children receive is relatively dismal and of poor quality relative to the high quantity and quality of output that they manage to produce after age 2 and that only an advanced, innate capacity to decode and organize linguistic input can enable them to “get from here (prelinguistic infant) to there (linguistic child).” In “Constructing a Language,” Tomasello presents a contrasting theory of how the child acquires language: It is not a universal grammar that allows for language development. Rather, human cognition universals of communicative needs and vocal-auditory processing result in some language universals, such as nouns and verbs as expressions of reference and predication (p. 19). The author proposes that two sets of cognitive skills resulting from biological/phylogenetic adaptations are fundamental to the ontogenetic origins of language. These sets of inherited cognitive skills are intentionreading on the one hand and pattern-finding, on the other. Intention-reading skills encompass the prelinguistic infant’s capacities to share attention to outside events with other persons, establishing joint attentional frames, to understand other people’s communicative intentions, and to imitate the adult’s communicative intentions (an intersubjective form of imitation that requires symbolic understanding and perspective-taking). Pattern-finding skills include the ability of infants as young as 7 months old to analyze concepts and percepts (most relevant here, auditory or speech percepts) and create concrete or abstract categories that contain analogous items. Tomasello, a most prominent developmental scientist with research foci on child language acquisition and on social cognition and social learning in children and primates, succinctly and clearly introduces the major points of his theory and his views on the origins of language in the initial chapters. In subsequent chapters, he delves into the details by covering most language acquisition domains, namely, word (lexical) learning, syntax, and morphology and conversation, narrative, and extended discourse. Although one of the remaining domains (pragmatics) is at the core of his theory and permeates the text throughout, the relative paucity of passages explicitly devoted to discussing acquisition and proBOOK REVIEWS

Constructing a language: A usage-based theory of language acquisition

Tunable slow and fast light with large bandwidth in the band-edge of gain spectrum of the wide band fiber optical parametric amplifier

A simple approach for optically generating monocycle and doublet UWB pulses in a single SOA is proposed and experimentally demonstrated. The scheme is switchable in both pulse shape and pulse polarity.

https://ieeexplore.ieee.org/iel5/5999540/6014653/06015250.pdf

Photonic switchable ultra-wideband (UWB) pulse generation in a single SOA

We design a cost-effective broadband radio over fiber (RoF) transceiver based on 1310 nm 10 GbE commercial off the shelf (COTS) optical components, with up to 4.3 GHz bandwidth. The suppression of 3rd intermodulation distortion (IMD3) is as high as 50dBc, and the spurious-free dynamic range (SFDR) of RoF links based on this transceiver reaches 85 dB/Hz2/3. An error vector magnitude (EVM) of 3% is also achieved in the transmission of vector modulation signals, and specifically in transmitting 54 Mbps 64QAM-OFDM signals over frequencies ranging from 100 MHz to 4.3 GHz.

A cost-effective broadband RoF transceiver based on COTS GbE optical components

Semiconductor saturable absorber mirror (SESAM) mode-locked all-polarization maintaining (PM) fiber oscillator with a fundamental repetition rate up to 1 GHz centered around1558 nm was demonstrated. With a 450 mW incident pump power, the oscillator is operating at the soliton mode-locked regime due to intracavity anomalous dispersion. The spectral width and compressed pulse duration is 9.4 nm and 379 fs, respectively. The obtained pulse maintains a good pulse quality with an average power of 7.46 mW, corresponding to a pulse energy of 7.3 pJ. The mode-locked fiber oscillator is compact, SESAM burnt-free and robust with an all-polarization maintaining fiber configuration.

1-GHz, compact mode locked femtosecond all-polarization maintaining erbium-doped fiber oscillator

We proposed and demonstrated a RF-to-Digital photonic link for relaying microwave signals over an optical fiber and linear converting the microwave signal to digital domain. The system uses two cascaded polarization modulators to achieve microwave-optoeletronic mixer. Two parallel polarization controllers (PC) and polarization beam splitter (PBS) are connected to the output of receiver PolM in order to realize I/Q intensity demodulation. We further show that by simply merging the coherent demodulation with DSP, the dynamic range of the system is significantly improved to 112dB-Hz2/3 at 14 GHz. In this scheme, the fluctuation of optical phase noise has no impact on the stable performance of the system.

https://www.ursi.org/Proceedings/ProcGA14/papers/ursi_paper2372.pdf

Kun Xu

Papers

Tunable slow and fast light with large bandwidth in the band-edge of gain spectrum of the wide band fiber optical parametric amplifier

Photonic switchable ultra-wideband (UWB) pulse generation in a single SOA

A cost-effective broadband RoF transceiver based on COTS GbE optical components

1-GHz, compact mode locked femtosecond all-polarization maintaining erbium-doped fiber oscillator

Linearity performance of optoelectronic frequency down-conversion by using dual-series polarization modulator