Journal of the Optical Society of Korea最新文献_第2页

Bandwidth Allocation Under Multi-Level Service Guarantees of Downlink in the VLC-OFDM System VLC-OFDM系统下行多级服务保障下的带宽分配

Journal of the Optical Society of Korea Pub Date : 2016-12-25 DOI: 10.3807/JOSK.2016.20.6.704

Shuangxing Liu, Xuefen Chi, Linlin Zhao

{"title":"Bandwidth Allocation Under Multi-Level Service Guarantees of Downlink in the VLC-OFDM System","authors":"Shuangxing Liu, Xuefen Chi, Linlin Zhao","doi":"10.3807/JOSK.2016.20.6.704","DOIUrl":"https://doi.org/10.3807/JOSK.2016.20.6.704","url":null,"abstract":"In this paper, we explore a low-complex bandwidth allocation (BA) scheme with multi-level service guarantees in VLC-OFDM systems. Effective capacity theory, which evaluates wireless channel capacity from a novel view, is utilized to model the system capacity under delay QoS constraints of the link layer. Since intensity modulation of light is used in the system, problems caused by frequency selectivity can be neglected. Then, the BA problem can be formulated as an integer programming problem and it is further relaxed and transformed into a concave one. Lagrangian formulation is used to reformulate the concave problem. Considering the inefficiency of traditional gradient-based schemes and the demand for distributed implementation in local area networks, we localize the global parameters and propose a quasi-distributed quadratic allocation algorithm to provide two-level service guarantees, the first level is QoS oriented, and the second level is QoE oriented. Simulations have shown the efficient performance of the proposed algorithm. The users with more stringent QoS requirements require more subcarriers to guarantee their statistical delay QoS requirements. We also analyze the effect of subcarrier granularity on the aggregate effective capacity via simulations.","PeriodicalId":49986,"journal":{"name":"Journal of the Optical Society of Korea","volume":"20 1","pages":"704-715"},"PeriodicalIF":0.0,"publicationDate":"2016-12-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70141166","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 2

High Power Switchable Dual-Wavelength Linear Polarized Yb-Dozped Fiber Laser around 1120 nm 高功率可切换双波长线偏振光纤激光器约1120nm

Journal of the Optical Society of Korea Pub Date : 2016-12-25 DOI: 10.3807/JOSK.2016.20.6.716

Xiaojuan Liu, Bangcai Huang, Gongxiang Wei, Ke-zhen Han, Yan Huang, Fangfang Liu

{"title":"High Power Switchable Dual-Wavelength Linear Polarized Yb-Dozped Fiber Laser around 1120 nm","authors":"Xiaojuan Liu, Bangcai Huang, Gongxiang Wei, Ke-zhen Han, Yan Huang, Fangfang Liu","doi":"10.3807/JOSK.2016.20.6.716","DOIUrl":"https://doi.org/10.3807/JOSK.2016.20.6.716","url":null,"abstract":"A single-and dual-wavelength switchable polarized Yb-doped double-clad fiber laser around 1120 nm based on a pair of fiber Bragg gratings (FBGs) is demonstrated. The polarization-maintaining (PM) linear cavity is composed of a double clad PM Yb-doped fiber (YDF) and a pair of PM FBGs. The laser can operate in stable dual-wavelength or wavelength-switching modes due to the polarization hole burning (PHB) and the spatial hole burning (SHB) enhanced by the PM linear cavity. In dual-wavelength operation, the two orthogonally polarized wavelengths are centered at 1118.912 nm and 1119.152 nm, with an interval of 0.24 nm and a signal to noise ratio (SNR) of 35 dB. The maximum output power is 14.67 W when the launched LD pump is 24 W corresponding to an optical efficiency of 61.1%. The lasing lines switchover may be realized by adjusting the polarization controller (PC) fitted in the cavity. The two single-wavelengths are 1118.912 nm and 1119.152 nm. When the injected LD pump is 24 W, the highest output powers are 7.68 W and 8.64 W corresponding to optical efficiencies of 32% and 36% respectively. The spectral linewidth of the lasing lines are 0.075 nm and 0.07 nm, and the average numerical values of PER are 20.3 dB and 19.9 dB, respectively.","PeriodicalId":49986,"journal":{"name":"Journal of the Optical Society of Korea","volume":"20 1","pages":"716-721"},"PeriodicalIF":0.0,"publicationDate":"2016-12-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70141175","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 2

Methods and Systems for High-temperature Strain Measurement of the Main Steam Pipe of a Boiler of a Power Plant While in Service 电厂在役锅炉主蒸汽管道高温应变测量方法与系统

Journal of the Optical Society of Korea Pub Date : 2016-12-25 DOI: 10.3807/JOSK.2016.20.6.770

Chengxie Guang, Feng Qibo, Ding Keqin

引用次数: 4

LED Lens for Rectangular Beam with Small Divergence Angles 用于小发散角矩形光束的LED透镜

Journal of the Optical Society of Korea Pub Date : 2016-12-25 DOI: 10.3807/JOSK.2016.20.6.739

Dianhong Liu, Xiao-hui Zhang, Shuang Zhang

引用次数: 3

Dynamic Modulation Transfer Function Analysis of Images Blurred by Sinusoidal Vibration 正弦振动模糊图像的动态调制传递函数分析

Journal of the Optical Society of Korea Pub Date : 2016-12-25 DOI: 10.3807/JOSK.2016.20.6.762

Yan Du, Yalin Ding, Yongsen Xu, Chongshang Sun

引用次数: 5

Infrared-to-Visible Up-conversion in Er-Pr-Yb Triply Doped Oxyfluoride Glass Ceramics Er-Pr-Yb三掺氟氧玻璃陶瓷的红外-可见光上转换

Journal of the Optical Society of Korea Pub Date : 2016-12-25 DOI: 10.3807/JOSK.2016.20.6.778

Su-A Song, K. Lim

引用次数: 1

A Numerical Study of Different Types of Collimators for a High-Resolution Preclinical CdTe Pixelated Semiconductor SPECT System 高分辨率CdTe像素化半导体SPECT系统中不同类型准直器的数值研究

Journal of the Optical Society of Korea Pub Date : 2016-12-25 DOI: 10.3807/JOSK.2016.20.6.663

Hyun-Woo Jeong, Jong Seok Kim, S. Bae, Kanghyen Seo, Seung Hun Kim, S. Kang, Dong Jin Shin, Chang-Lae Lee, Kyuseok Kim, Youngjin Lee

{"title":"A Numerical Study of Different Types of Collimators for a High-Resolution Preclinical CdTe Pixelated Semiconductor SPECT System","authors":"Hyun-Woo Jeong, Jong Seok Kim, S. Bae, Kanghyen Seo, Seung Hun Kim, S. Kang, Dong Jin Shin, Chang-Lae Lee, Kyuseok Kim, Youngjin Lee","doi":"10.3807/JOSK.2016.20.6.663","DOIUrl":"https://doi.org/10.3807/JOSK.2016.20.6.663","url":null,"abstract":"In single-photon-emission computed tomography (SPECT) with a pixelated semiconductor detector (PSD), not only pinhole collimators but also parallel-hole collimators are often used in preclinical nuclear-medicine imaging systems. The purpose of this study was to evaluate and compare pinhole and parallel-hole collimators in a PSD. For that purpose, we paired a PID 350 (Ajat Oy Ltd., Finland) CdTe PSD with each of the four collimators most frequently used in preclinical nuclear medicine: (1) a pinhole collimator, and (2) low-energy high-resolution (LEHR), (3) low-energy general-purpose (LEGP), and (4) low-energy high-sensitivity (LEHS) parallel-hole collimators. The sensitivity and spatial resolution of each collimator was evaluated using a point source and a hot-rod phantom. The highest sensitivity was achieved using LEHS, followed by LEGP, LEHR, and pinhole. Also, at a source-to-collimator distance of 2 cm, the spatial resolution was 1.63, 2.05, 2.79, and 3.45 mm using pinhole, LEHR, LEGP, and LEHS, respectively. The reconstructed hot-rod phantom images showed that the pinhole collimator and the LEHR parallel-hole collimator give a fine spatial resolution for preclinical SPECT with PSD. In conclusion, we successfully compared different types of collimators for a preclinical pixelated semiconductor SPECT system.","PeriodicalId":49986,"journal":{"name":"Journal of the Optical Society of Korea","volume":"20 1","pages":"663-668"},"PeriodicalIF":0.0,"publicationDate":"2016-12-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70140957","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Single Shot White Light Interference Microscopy for 3D Surface Profilometry Using Single Chip Color Camera 单镜头白光干涉显微镜用于三维表面轮廓测量的单芯片彩色相机

Journal of the Optical Society of Korea Pub Date : 2016-12-25 DOI: 10.3807/JOSK.2016.20.6.784

V. Srivastava, M. Inam, Ranjeet Kumar, D. Mehta

引用次数: 6

Proposal for Optical One-time Password Authentication Using Digital Holography 基于数字全息的光学一次性密码认证方案

Journal of the Optical Society of Korea Pub Date : 2016-12-25 DOI: 10.3807/JOSK.2016.20.6.722

Seok-Hee Jeon, S. Gil

{"title":"Proposal for Optical One-time Password Authentication Using Digital Holography","authors":"Seok-Hee Jeon, S. Gil","doi":"10.3807/JOSK.2016.20.6.722","DOIUrl":"https://doi.org/10.3807/JOSK.2016.20.6.722","url":null,"abstract":"A new optical one-time password (OTP) authentication method using digital holography is proposed, which enhances security strength in the authentication system. A challenge-response optical OTP algorithm based on two-factor authentication is presented using two-step phase-shifting digital holography, and two-way authentication is also performed using challenge-response handshake in both directions. Identification (ID), password (PW), and OTP are encrypted with a shared key by applying phase-shifting digital holography, and these encrypted pieces of information are verified by each party by means of the shared key. The encrypted digital holograms are obtained by Fourier-transform holography and are recorded on a CCD with 256 quantized gray-level intensities. Because the intensity pattern of such an encrypted digital hologram is distributed randomly, it guards against a replay attack and results in higher security level. The proposed method has advantages, in that it does not require a time-synchronized OTP, and can be applied to various authentication applications. Computer experiments show that the proposed method is feasible for high-security OTP authentication.","PeriodicalId":49986,"journal":{"name":"Journal of the Optical Society of Korea","volume":"20 1","pages":"722-732"},"PeriodicalIF":0.0,"publicationDate":"2016-12-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70141218","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

Continuous Viewing Angle Distribution Control of Liquid Crystal Displays Using Polarization-Dependent Prism Array Film Stacked on Directional Backlight Unit 在定向背光单元上叠加偏光相关棱镜阵列薄膜的液晶显示器连续视角分布控制

Journal of the Optical Society of Korea Pub Date : 2016-12-25 DOI: 10.3807/JOSK.2016.20.6.799

Min-Kyu Park, Heewon Park, Kyung‐Il Joo, Hee-Dong Jeong, Jun‐Chan Choi, Hak‐Rin Kim

引用次数: 2