Showing papers by "Samsung published in 2014"

What Will 5G Be

Abstract: What will 5G be? What it will not be is an incremental advance on 4G. The previous four generations of cellular technology have each been a major paradigm shift that has broken backward compatibility. Indeed, 5G will need to be a paradigm shift that includes very high carrier frequencies with massive bandwidths, extreme base station and device densities, and unprecedented numbers of antennas. However, unlike the previous four generations, it will also be highly integrative: tying any new 5G air interface and spectrum together with LTE and WiFi to provide universal high-rate coverage and a seamless user experience. To support this, the core network will also have to reach unprecedented levels of flexibility and intelligence, spectrum regulation will need to be rethought and improved, and energy and cost efficiencies will become even more critical considerations. This paper discusses all of these topics, identifying key challenges for future research and preliminary 5G standardization activities, while providing a comprehensive overview of the current literature, and in particular of the papers appearing in this special issue.

Spatially Sparse Precoding in Millimeter Wave MIMO Systems

Abstract: Millimeter wave (mmWave) signals experience orders-of-magnitude more pathloss than the microwave signals currently used in most wireless applications and all cellular systems. MmWave systems must therefore leverage large antenna arrays, made possible by the decrease in wavelength, to combat pathloss with beamforming gain. Beamforming with multiple data streams, known as precoding, can be used to further improve mmWave spectral efficiency. Both beamforming and precoding are done digitally at baseband in traditional multi-antenna systems. The high cost and power consumption of mixed-signal devices in mmWave systems, however, make analog processing in the RF domain more attractive. This hardware limitation restricts the feasible set of precoders and combiners that can be applied by practical mmWave transceivers. In this paper, we consider transmit precoding and receiver combining in mmWave systems with large antenna arrays. We exploit the spatial structure of mmWave channels to formulate the precoding/combining problem as a sparse reconstruction problem. Using the principle of basis pursuit, we develop algorithms that accurately approximate optimal unconstrained precoders and combiners such that they can be implemented in low-cost RF hardware. We present numerical results on the performance of the proposed algorithms and show that they allow mmWave systems to approach their unconstrained performance limits, even when transceiver hardware constraints are considered.

Millimeter-wave beamforming as an enabling technology for 5G cellular communications: theoretical feasibility and prototype results

Abstract: The ever growing traffic explosion in mobile communications has recently drawn increased attention to the large amount of underutilized spectrum in the millimeter-wave frequency bands as a potentially viable solution for achieving tens to hundreds of times more capacity compared to current 4G cellular networks. Historically, mmWave bands were ruled out for cellular usage mainly due to concerns regarding short-range and non-line-of-sight coverage issues. In this article, we present recent results from channel measurement campaigns and the development of advanced algorithms and a prototype, which clearly demonstrate that the mmWave band may indeed be a worthy candidate for next generation (5G) cellular systems. The results of channel measurements carried out in both the United States and Korea are summarized along with the actual free space propagation measurements in an anechoic chamber. Then a novel hybrid beamforming scheme and its link- and system-level simulation results are presented. Finally, recent results from our mmWave prototyping efforts along with indoor and outdoor test results are described to assert the feasibility of mmWave bands for cellular usage.

Organic light-emitting device

Abstract: The present invention provides a heterocyclic compound and an organic light-emitting device including the heterocyclic compound. The organic light-emitting devices using the heterocyclic compounds have high-efficiency, low driving voltage, high luminance and long lifespan.

Highly Stretchable Resistive Pressure Sensors Using a Conductive Elastomeric Composite on a Micropyramid Array

Abstract: A stretchable resistive pressure sensor is achieved by coating a compressible substrate with a highly stretchable electrode. The substrate contains an array of microscale pyramidal features, and the electrode comprises a polymer composite. When the pressure-induced geometrical change experienced by the electrode is maximized at 40% elongation, a sensitivity of 10.3 kPa(-1) is achieved.

Understanding the Degradation Mechanisms of LiNi0.5Co0.2Mn0.3O2 Cathode Material in Lithium Ion Batteries

Abstract: LiNixCoyMnzO2 (NCM, 0 ≤ x,y,z 4.3 V) required for high capacity is inevitably accompanied by a more rapid capacity fade over numerous cycles. Here, the degradation mechanisms of LiNi0.5Co0.2Mn0.3O2 are investigated during cycling under various cutoff voltage conditions. The surface lattice structures of LiNi0.5Co0.2Mn0.3O2 are observed to suffer from an irreversible transformation; the type of transformation depends on the cutoff voltage conditions. The surface of the pristine rhombohedral phase tends to transform into a mixture of spinel and rock salt phases. Moreover, the formation of the rock salt phase is more dominant under a higher voltage operation (≈4.8 V), which is attributable to the highly oxidative environment that triggers the oxygen loss from the surface of the material. The presence of the ionically insulating rock salt phase may result in sluggish kinetics, thus deteriorating the capacity retention. This implies that the prevention of surface structural degradation can provide the means to produce and retain high capacity, as well as stabilize the cycle life of LiNi0.5Co0.2Mn0.3O2 during high-voltage operations.

Wafer-Scale Growth of Single-Crystal Monolayer Graphene on Reusable Hydrogen-Terminated Germanium

Abstract: The uniform growth of single-crystal graphene over wafer-scale areas remains a challenge in the commercial-level manufacturability of various electronic, photonic, mechanical, and other devices based on graphene. Here, we describe wafer-scale growth of wrinkle-free single-crystal monolayer graphene on silicon wafer using a hydrogen-terminated germanium buffer layer. The anisotropic twofold symmetry of the germanium (110) surface allowed unidirectional alignment of multiple seeds, which were merged to uniform single-crystal graphene with predefined orientation. Furthermore, the weak interaction between graphene and underlying hydrogen-terminated germanium surface enabled the facile etch-free dry transfer of graphene and the recycling of the germanium substrate for continual graphene growth.

The Role of Intrinsic Defects in Methylammonium Lead Iodide Perovskite.

Abstract: One of the major merits of CH3NH3PbI3 perovskite as an efficient absorber material for the photovoltaic cell is its long carrier lifetime. We investigate the role of the intrinsic defects of CH3NH3PbI3 on its outstanding photovoltaic properties using density-functional studies. Two types of defects are of interest, i.e., Schottky defects and Frenkel defects. Schottky defects, such as PbI2 and CH3NH3I vacancy, do not make a trap state, which can reduce carrier lifetime. Elemental defects like Pb, I, and CH3NH3 vacancies derived from Frenkel defects act as dopants, which explains the unintentional doping of methylammonium lead halides (MALHs). The absence of gap states from intrinsic defects of MALHs can be ascribed to the ionic bonding from organic–inorganic hybridization. These results explain why the perovskite MALHs can be an efficient semiconductor, even when grown using simple solution processes. It also suggests that the n-/p-type can be efficiently manipulated by controlling growth processes.

Organic light emitting display apparatus

Abstract: An organic light emitting display apparatus that has high (or improved) contrast and/or impact resistance. The organic light emitting display apparatus includes: a substrate; an organic light emitting device on the substrate to display an image; a sealing member on the organic light emitting device; a semitransparent film on a surface of the sealing member facing away from the organic light emitting device to transmit a portion of external light and to reflect another portion of the external light; a passivation film on the semitransparent film to protect the semitransparent film; and a transmissive black layer between the sealing member and the organic light emitting device to increase contrast, wherein the semitransparent film has a refractive index greater than that of the passivation film.

Organic light emitting display

Abstract: An organic light-emitting display includes a first substrate which includes a pixel region, and an encapsulation region which surrounds the pixel region, an organic light-emitting device which is located in the pixel region, a sealant which is located in the encapsulation region, and a dummy metal which is interposed between the first substrate and the sealant, where the encapsulation region includes a first encapsulation region and a second encapsulation region which is adjacent to the first encapsulation region, and the dummy metal is located in the first encapsulation region.

Study and prototyping of practically large-scale mmWave antenna systems for 5G cellular devices

Abstract: This article discusses the challenges, benefits and approaches associated with realizing largescale antenna arrays at mmWave frequency bands for future 5G cellular devices. Key design considerations are investigated to deduce a novel and practical phased array antenna solution operating at 28 GHz with near spherical coverage. The approach is further evolved into a first-of- a-kind cellular phone prototype equipped with mmWave 5G antenna arrays consisting of a total of 32 low-profile antenna elements. Indoor measurements are carried out using the presented prototype to characterize the proposed mmWave antenna system using 16-QAM modulated signals with 27.925 GHz carrier frequency. The biological implications due to the absorbed electromagnetic waves when using mmWave cellular devices are studied and compared in detail with those of 3/4G cellular devices.

Stretchable Energy-Harvesting Tactile Electronic Skin Capable of Differentiating Multiple Mechanical Stimuli Modes

Abstract: The first stretchable energy-harvesting electronic-skin device capable of differentiating and generating energy from various mechanical stimuli, such as normal pressure, lateral strain, bending, and vibration, is presented. A pressure sensitivity of 0.7 kPa(-1) is achieved in the pressure region <1 kPa with power generation of tens of μW cm(-2) from a gentle finger touch.

What Will 5G Be

Abstract: What will 5G be? What it will not be is an incremental advance on 4G. The previous four generations of cellular technology have each been a major paradigm shift that has broken backwards compatibility. And indeed, 5G will need to be a paradigm shift that includes very high carrier frequencies with massive bandwidths, extreme base station and device densities and unprecedented numbers of antennas. But unlike the previous four generations, it will also be highly integrative: tying any new 5G air interface and spectrum together with LTE and WiFi to provide universal high-rate coverage and a seamless user experience. To support this, the core network will also have to reach unprecedented levels of flexibility and intelligence, spectrum regulation will need to be rethought and improved, and energy and cost efficiencies will become even more critical considerations. This paper discusses all of these topics, identifying key challenges for future research and preliminary 5G standardization activities, while providing a comprehensive overview of the current literature, and in particular of the papers appearing in this special issue.

A flexible bimodal sensor array for simultaneous sensing of pressure and temperature.

Abstract: Diverse signals generated from the sensing elements embedded in flexible electronic skins (e-skins) are typically interfered by strain energy generated through processes such as touching, bending, stretching or twisting. Herein, we demonstrate a flexible bimodal sensor that can separate a target signal from the signal by mechanical strain through the integration of a multi-stimuli responsive gate dielectric and semiconductor channel into the single field-effect transistor (FET) platform.

Transparent Flexible Graphene Triboelectric Nanogenerators

Abstract: S. Kim, Dr. M. K. Gupta, K. Y. Lee, K.-S. Shin, S. K. Kim, K. H. Lee, Prof. S.-W. Kim School of Advanced Materials Science and Engineering Sungkyunkwan University (SKKU) Suwon 440–746 , Republic of Korea E-mail: kimsw1@skku.edu A. Sohn, Prof. D.-W. Kim School of Department of Physics Ewha Womens University Seoul 120–750 , Republic of Korea T. Y. Kim, D. Kim, Prof. S.-W. Kim SKKU Advanced Institute of Nanotechnology (SAINT) Center for Human Interface Nanotechnology (HINT) SKKU-Samsung Graphene Center Sungkyunkwan University (SKKU) Suwon 440–746 , Republic of Korea Dr. H.-J. Shin Samsung Advanced Institute of Technology Yongin 446–712 , Republic of Korea

Display device and method of manufacturing the same

Abstract: A display device and a manufacturing method thereof The display device includes a substrate including at least one plastic layer; and a display layer on the substrate and including a plurality of signal lines and a plurality of pixels The substrate includes at least one antistatic layer

Pixel and organic light emitting display device using the same

Abstract: A pixel includes a pixel circuit to control an amount of current supplied from a first power source to an organic light emitting diode (OLED) based on a data signal. At least one first transistor is located in a current path between the first power source and OLED. A second transistor is coupled between a gate electrode of the at least one first transistor and an emission control line through which an emission control signal is supplied. The emission control line controls a state of the at least one first transistor, and the second transistor turns on or off based on the data signal.

Flutter-driven triboelectrification for harvesting wind energy

Abstract: The harvesting of electrical energy from renewable sources remains an ongoing scientific focus. Here, the authors report a triboelectric generator that is capable of harnessing energy from the wind via a flutter motion, with the output of the device dependent on the precise motion caused by the wind.

Organic light emitting display device and method of manufacturing the same

Abstract: An organic light emitting display (OLED) device includes a substrate, a plurality of first electrodes, a plurality of light emitting layers, a second electrode, a power supply line, a third electrode, and an encapsulation member The third electrode that is formed on the power supply line and the second electrode that is formed on the light emitting layers extend to a contact region that is in a peripheral region of the substrate The third electrode and the second electrodes have an uneven pattern in the contact region

Vertical Alignments of Graphene Sheets Spatially and Densely Piled for Fast Ion Diffusion in Compact Supercapacitors

Abstract: Supercapacitors with porous carbon structures have high energy storage capacity. However, the porous nature of the carbon electrode, composed mainly of carbon nanotubes (CNTs) and graphene oxide (GO) derivatives, negatively impacts the volumetric electrochemical characteristics of the supercapacitors because of poor packing density (<0.5 g cm–3). Herein, we report a simple method to fabricate highly dense and vertically aligned reduced graphene oxide (VArGO) electrodes involving simple hand-rolling and cutting processes. Because of their vertically aligned and opened-edge graphene structure, VArGO electrodes displayed high packing density and highly efficient volumetric and areal electrochemical characteristics, very fast electrolyte ion diffusion with rectangular CV curves even at a high scan rate (20 V/s), and the highest volumetric capacitance among known rGO electrodes. Surprisingly, even when the film thickness of the VArGO electrode was increased, its volumetric and areal capacitances were maintained.

Over 40 cd/A efficient green quantum dot electroluminescent device comprising uniquely large-sized quantum dots.

Abstract: Green CdSe@ZnS quantum dots (QDs) of 9.5 nm size with a composition gradient shell are first prepared by a single-step synthetic approach, and then 12.7 nm CdSe@ZnS/ZnS QDs, the largest among ZnS-shelled visible-emitting QDs available to date, are obtained through the overcoating of an additional 1.6 nm thick ZnS shell. Two QDs of CdSe@ZnS and CdSe@ZnS/ZnS are incorporated into the solution-processed hybrid QD-based light-emitting diode (QLED) structure, where the QD emissive layer (EML) is sandwiched by poly(9-vinlycarbazole) and ZnO nanoparticles as hole and electron-transport layers, respectively. We find that the presence of an additional ZnS shell makes a profound impact on device performances such as luminance and efficiencies. Compared to CdSe@ZnS QD-based devices the efficiencies of CdSe@ZnS/ZnS QD-based devices are overwhelmingly higher, specifically showing unprecedented values of peak current efficiency of 46.4 cd/A and external quantum efficiency of 12.6%. Such excellent results are likely att...

A Chain Structure of Switched Capacitor for Improved Cell Balancing Speed of Lithium-Ion Batteries

Abstract: Among various active cell balancing circuits, a switched capacitor circuit is promising because it can be implemented with low cost and small size. However, when the switched capacitor is applied in the lithium-ion battery, cell balancing speed is generally slow when the number of batteries is high. Therefore, this paper proposes the chain structure of the switched capacitor to increase balancing speed, particularly among outer cells. In this paper, the cell balancing principle of the conventional switched capacitor is explained, and the reason why slow cell balancing of the switched capacitor is shown in the lithium-ion battery is analyzed. To improve cell balancing speed, two circuits with chain structure are proposed. The balancing performance of the proposed circuits is confirmed by computer simulation, and a comparison between conventional and proposed circuits is presented. The theoretical analysis on the cell balancing speed of conventional structures and the proposed chain structure is also shown in this paper. Experimental tests were carried out to verify the validity of the proposed structures, and the experimental results show an improved balancing performance of the proposed circuit.

Display apparatus and control method thereof

Abstract: A display apparatus includes an image processor which processes an image to display an image content; a display unit which displays thereon an image content that is processed by the image processor; and a controller which displays a user interface (UI) menu including a plurality of UI items to search the image content, as one of a two-dimensional (2D) layout by which the plurality of UI items are arranged in a 2D manner, and a three-dimensional (3D) layout by which the plurality of UI items are arranged in a 3D manner , and changes displaying the one of the layouts to display the other of the layouts according to a user's command while maintaining a continuity of the arrangement of the plurality of UI items. Accordingly, search for an image content can be efficiently performed by using a UI menu.

Preserving Statistical Validity in Adaptive Data Analysis

Abstract: A great deal of effort has been devoted to reducing the risk of spurious scientific discoveries, from the use of sophisticated validation techniques, to deep statistical methods for controlling the false discovery rate in multiple hypothesis testing. However, there is a fundamental disconnect between the theoretical results and the practice of data analysis: the theory of statistical inference assumes a fixed collection of hypotheses to be tested, or learning algorithms to be applied, selected non-adaptively before the data are gathered, whereas in practice data is shared and reused with hypotheses and new analyses being generated on the basis of data exploration and the outcomes of previous analyses. In this work we initiate a principled study of how to guarantee the validity of statistical inference in adaptive data analysis. As an instance of this problem, we propose and investigate the question of estimating the expectations of $m$ adaptively chosen functions on an unknown distribution given $n$ random samples. We show that, surprisingly, there is a way to estimate an exponential in $n$ number of expectations accurately even if the functions are chosen adaptively. This gives an exponential improvement over standard empirical estimators that are limited to a linear number of estimates. Our result follows from a general technique that counter-intuitively involves actively perturbing and coordinating the estimates, using techniques developed for privacy preservation. We give additional applications of this technique to our question.

Robot cleaner and control method thereof

Abstract: Disclosed herein are a robot cleaner having an improved travel pattern and a control method thereof. The robot cleaner performs cleaning using zigzag travel as a basic cleaning traveling manner, and then performs cleaning using random travel as a finishing cleaning traveling manner so as to clean areas skipped during the zigzag travel. The robot cleaner performs the zigzag travel while maintaining a designated interval with a travel route proceeding to a wall regardless of a direction proceeding to the wall, and employs an improved zigzag travel method to maintain a zigzag travel pattern, if the robot cleaner senses an obstacle during the zigzag travel.

Dye-sensitized MoS2 photodetector with enhanced spectral photoresponse.

Abstract: We fabricated dye-sensitized MoS2 photodetectors that utilized a single-layer MoS2 treated with rhodamine 6G (R6G) organic dye molecules (with an optical band gap of 2.38 eV or 521 nm). The proposed photodetector showed an enhanced performance with a broad spectral photoresponse and a high photoresponsivity compared with the properties of the pristine MoS2 photodetectors. The R6G dye molecules deposited onto the MoS2 layer increased the photocurrent by an order of magnitude due to charge transfer of the photoexcited electrons from the R6G molecules to the MoS2 layer. Importantly, the photodetection response extended to the infrared (λ < 980 nm, which corresponded to about half the energy band gap of MoS2), thereby distinguishing the device performance from that of a pristine MoS2 device, in which detection was only possible at wavelengths shorter than the band gap of MoS2, i.e., λ < 681 nm. The resulting device exhibited a maximum photoresponsivity of 1.17 AW–1, a photodetectivity of 1.5 × 107 Jones, and ...

Current-induced transition from particle-by-particle to concurrent intercalation in phase-separating battery electrodes

Abstract: Many battery electrodes contain ensembles of nanoparticles that phase-separate on (de)intercalation. In such electrodes, the fraction of actively intercalating particles directly impacts cycle life: a vanishing population concentrates the current in a small number of particles, leading to current hotspots. Reports of the active particle population in the phase-separating electrode lithium iron phosphate (LiFePO4; LFP) vary widely, ranging from near 0% (particle-by-particle) to 100% (concurrent intercalation). Using synchrotron-based X-ray microscopy, we probed the individual state-of-charge for over 3,000 LFP particles. We observed that the active population depends strongly on the cycling current, exhibiting particle-by-particle-like behaviour at low rates and increasingly concurrent behaviour at high rates, consistent with our phase-field porous electrode simulations. Contrary to intuition, the current density, or current per active internal surface area, is nearly invariant with the global electrode cycling rate. Rather, the electrode accommodates higher current by increasing the active particle population. This behaviour results from thermodynamic transformation barriers in LFP, and such a phenomenon probably extends to other phase-separating battery materials. We propose that modifying the transformation barrier and exchange current density can increase the active population and thus the current homogeneity. This could introduce new paradigms to enhance the cycle life of phase-separating battery electrodes.

Semiconductor devices and methods of manufacturing the same

Abstract: Provided are a semiconductor device, which can facilitate a salicide process and can prevent a gate from being damaged due to misalign, and a method of manufacturing of the semiconductor device. The method includes forming a first insulation layer pattern on a substrate having a gate pattern and a source/drain region formed at both sides of the gate pattern, the first insulation layer pattern having an exposed portion of the source/drain region, forming a silicide layer on the exposed source/drain region, forming a second insulation layer on the entire surface of the substrate to cover the first insulation layer pattern and the silicide layer, and forming a contact hole in the second insulation layer to expose the silicide layer.