Some remarks on Thurston metric and hyperbolic metric

Zongliang Sun 대한수학회 2016 대한수학회보 Vol.53 No.2

In this paper, we study the relations between the Thurston metric and the hyperbolic metric on a closed surface of genus $g \geq 2.$ We show a rigidity result which says if there is an inequality between the marked length spectra of these two metrics, then they are isotopic. We obtain some inequalities on length comparisons between these metrics. Besides, we show certain distance distortions under conformal graftings, with respect to the Teichm\"uller metric, the length spectrum metric and Thurston's asymmetric metrics.

Release Mechanism and pH Responsiveness of Starch-Based Polymers

Zongliang Kou,Detian Dou,Jiayi Zhu,Yinyin Mai,Herui Yi,Lihong Lan,Ping Lan 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2019 NANO Vol.14 No.11

Amphiphilic polymer carriers (PEG–St–R) were prepared from cassava starch and their pH response was investigated. First, hydrophobic tapioca starch polymer (St–R) was prepared with octyl acyl as the hydrophobic group. The hydrophilic group polyethylene glycol (mPEG) was then introduced into the polymer by esterification to produce amphiphilic tapioca starch polymer (PEG–St–R). Its self-assembly behavior was characterized using fluorescent probes. The morphology of PEG–St–R was investigated by transmission electron microscopy (TEM). Loading of the anti-cancer drug curcumin was used to assess the delivery and slow-release performance of the amphiphilic tapioca starch polymer. Cumulative drug release was explored at various pH conditions, with the greatest release from drug-loaded micelles being observed under acidic conditions and stable in a neutral environment. These results provide a theoretical basis for the preparation of pH-responsive nanomicelle carriers, and a platform for the preparation of novel amphiphilic starch-based polymers.

SOME REMARKS ON THURSTON METRIC AND HYPERBOLIC METRIC

Sun, Zongliang Korean Mathematical Society 2016 대한수학회보 Vol.53 No.2

In this paper, we study the relations between the Thurston metric and the hyperbolic metric on a closed surface of genus $g{\geq}2$. We show a rigidity result which says if there is an inequality between the marked length spectra of these two metrics, then they are isotopic. We obtain some inequalities on length comparisons between these metrics. Besides, we show certain distance distortions under conformal graftings, with respect to the $Teichm{\ddot{u}}ller$ metric, the length spectrum metric and Thurston's asymmetric metrics.

Side Information Extrapolation Using Motion-aligned Auto Regressive Model for Compressed Sensing based Wyner-Ziv Codec

( Ran Li ),( Zongliang Gan ),( Ziguan Cui ),( Minghu Wu ),( Xiuchang Zhu ) 한국인터넷정보학회 2013 KSII Transactions on Internet and Information Syst Vol.7 No.2

In this paper, we propose a compressed sensing (CS) based Wyner-Ziv (WZ) codec using motion-aligned auto regressive model (MAAR) based side information (SI) extrapolation to improve the compression performance of low-delay distributed video coding (DVC). In the CS based WZ codec, the WZ frame is divided into small blocks and CS measurements of each block are acquired at the encoder, and a specific CS reconstruction algorithm is proposed to correct errors in the SI using CS measurements at the decoder. In order to generate high quality SI, a MAAR model is introduced to improve the inaccurate motion field in auto regressive (AR) model, and the Tikhonov regularization on MAAR coefficients and overlapped block based interpolation are performed to reduce block effects and errors from over-fitting. Simulation experiments show that our proposed CS based WZ codec associated with MAAR based SI generation achieves better results compared to other SI extrapolation methods.

Laparoscopic radical cystectomy with pelvic lymph node dissection and ileal orthotopic neobladder by a total extraperitoneal approach: Our initial technique and short-term outcomes

Guanqun Zhu,Zongliang Zhang,Kai Zhao,Xinbao Yin,Yulian Zhang,Zhenlin Wang,Chen Li,Yuanming Sui,Xueyu Li,Han Yang,Nianzeng Xing,Ke Wang 대한비뇨의학회 2022 Investigative and Clinical Urology Vol.63 No.5

Purpose: With the increasing application of laparoscopic or robot-assisted radical cystectomy, a reliable and promising method is needed for reducing postoperative complications. We describe the short-term outcomes of totally extraperitoneal laparoscopic radical cystectomy (TELRC) with extraperitoneal pelvic lymph node dissection (EPLND) and extraperitoneal ileal orthotopic neobladder (EION) techniques. Materials and Methods: From January 2020 to December 2021, we performed TELRC and EPLND with EION in 72 patients in our center. The accompanying video highlights our novel techniques. The patients’ demographic data, intraoperative data, and perioperative complications were collected, and short-term oncological and functional results are reported. Results: All procedures were technically successful without conversion to open surgery. The patients’ mean body mass index was 26.22±5.71. Median age was 57.51±12.34 years. Average hospital stay was 13.78±4.62 days. Median intraoperative blood loss was 112.92±88.56 mL. No blood transfusion was needed during the operations and only one blood transfusion was performed during the perioperative period. Mean operating time was 259.44±49.84 minutes. Average cost was US$9,875.71±1,873.08. Postoperative short-term complications included short-term ileus (n=3), infection (n=13), leakage of urine (n=11), and lymph fistula (n=7). One late complication of unilateral vesicoureteral anastomotic stenosis occurred. The mean follow-up was 13.42±8.77 months, and no patient developed local or systemic recurrence. The short-term follow-up and small cohort of patients limited our evaluation of outcomes. Conclusions: TELRC with PLND and EION was technically feasible and clinically promising, with a reduced potential harm of postoperative complications. Long-term follow-up and a larger cohort of patients are needed for further study.

Joint Spatial-Temporal Quality Improvement Scheme for H.264 Low Bit Rate Video Coding via Adaptive Frameskip

( Ziguan Cui ),( Zongliang Gan ),( Xiuchang Zhu ) 한국인터넷정보학회 2012 KSII Transactions on Internet and Information Syst Vol.6 No.1

Conventional rate control (RC) schemes for H.264 video coding usually regulate output bit rate to match channel bandwidth by adjusting quantization parameter (QP) at fixed full frame rate, and the passive frame skipping to avoid buffer overflow usually occurs when scene changes or high motions exist in video sequences especially at low bit rate, which degrades spatial-temporal quality and causes jerky effect. In this paper, an active content adaptive frame skipping scheme is proposed instead of passive methods, which skips subjectively trivial frames by structural similarity (SSIM) measurement between the original frame and the interpolated frame via motion vector (MV) copy scheme. The saved bits from skipped frames are allocated to coded key ones to enhance their spatial quality, and the skipped frames are well recovered based on MV copy scheme from adjacent key ones at the decoder side to maintain constant frame rate. Experimental results show that the proposed active SSIM-based frameskip scheme acquires better and more consistent spatial-temporal quality both in objective (PSNR) and subjective (SSIM) sense with low complexity compared to classic fixed frame rate control method JVT-G012 and prior objective metric based frameskip method.

No-reference Image Blur Assessment Based on Multi-scale Spatial Local Features

( Chenchen Sun ),( Ziguan Cui ),( Zongliang Gan ),( Feng Liu ) 한국인터넷정보학회 2020 KSII Transactions on Internet and Information Syst Vol.14 No.10

Blur is an important type of image distortion. How to evaluate the quality of blurred image accurately and efficiently is a research hotspot in the field of image processing in recent years. Inspired by the multi-scale perceptual characteristics of the human visual system (HVS), this paper presents a no-reference image blur/sharpness assessment method based on multi-scale local features in the spatial domain. First, considering various content has different sensitivity to blur distortion, the image is divided into smooth, edge, and texture regions in blocks. Then, the Gaussian scale space of the image is constructed, and the categorized contrast features between the original image and the Gaussian scale space images are calculated to express the blur degree of different image contents. To simulate the impact of viewing distance on blur distortion, the distribution characteristics of local maximum gradient of multi-resolution images were also calculated in the spatial domain. Finally, the image blur assessment model is obtained by fusing all features and learning the mapping from features to quality scores by support vector regression (SVR). Performance of the proposed method is evaluated on four synthetically blurred databases and one real blurred database. The experimental results demonstrate that our method can produce quality scores more consistent with subjective evaluations than other methods, especially for real burred images.

Direct kinematic method for exactly constructing influence lines of forces of statically indeterminate structures

Dixiong Yang,Guohai Chen,Zongliang Du 국제구조공학회 2015 Structural Engineering and Mechanics, An Int'l Jou Vol.54 No.4

Constructing the influence lines of forces of statically indeterminate structures is a traditional issue in structural engineering and mechanics. However, the existing kinematic method for establishing these force influence lines is an indirect or mixed approach by combining the force method with the theorem of reciprocal displacements, which is yet inconsistent with the kinematic method for statically determinate structure. This paper proposes the direct kinematic method in conjunction with the load-displacement differential relation for exactly constructing influence lines of reaction and internal forces of indeterminate structures. Firstly, through applying the principle of virtual displacement, the formula for influence lines of reaction and internal forces of indeterminate structure via direct kinematic method is derived based on the released structure. Then, a computational approach with a clear concept and unified procedure as well as wide applicability based on the load-displacement differential relation of beam is suggested to achieve conveniently the closed-form expression of force influence lines, and exactly draw them. Finally, three representative examples for constructing force influence lines of statically indeterminate beams and frame illustrate the superiority of the proposed method.

The rheological behavior of collagen dispersion/poly(vinyl alcohol) blends

Guoying Li,Guoli Lai,Zongliang 한국유변학회 2007 Korea-Australia rheology journal Vol.19 No.2

Blends of collagen dispersion (COL) with poly(vinyl alcohol) (PVA) in different weight ratios were investigated by oscillatory rheometry, Fourier transform-infrared spectroscopy and scanning electron microscopy. It was found that even with 80% of PVA, the COL/PVA blends behaved more like collagen dispersion than pure PVA solution in the dynamic thermal and frequency processing, for instance, a dominant elastic appearance (G'>G"), a similar shear thinning behavior and the thermal denaturation below 40C. However, influence on the blend behaviour by PVA was noticeable, for instance, an increase of dynamic denaturation temperature, the decreasing intensity of amide I, II and III bands as well as the diminishing irregular pores on the surface of blends. The interaction between collagen and PVA could be observed, especially at the regions with low content or high content of PVA.

Joint Overlapped Block Motion Compensation Using Eight-Neighbor Block Motion Vectors for Frame Rate Up-Conversion

( Ran Li ),( Minghu Wu ),( Zongliang Gan ),( Ziguan Cui ),( Xiuchang Zhu ) 한국인터넷정보학회 2013 KSII Transactions on Internet and Information Syst Vol.7 No.10

The traditional block-based motion compensation methods in frame rate up-conversion (FRUC) only use a single uniquely motion vector field. However, there will always be some mistakes in the motion vector field whether the advanced motion estimation (ME) and motion vector analysis (MA) algorithms are performed or not. Once the motion vector field has many mistakes, the quality of the interpolated frame is severely affected. In order to solve the problem, this paper proposes a novel joint overlapped block motion compensation method (8J-OBMC) which adopts motion vectors of the interpolated block and its 8-neighbor blocks to jointly interpolate the target block. Since the smoothness of motion filed makes the motion vectors of 8-neighbor blocks around the interpolated block quite close to the true motion vector of the interpolated block, the proposed compensation algorithm has the better fault-tolerant capability than traditional ones. Besides, the annoying blocking artifacts can also be effectively suppressed by using overlapped blocks. Experimental results show that the proposed method is not only robust to motion vectors estimated wrongly, but also can to reduce blocking artifacts in comparison with existing popular compensation methods.