Path Loss Exponent Estimation for Indoor Wireless Sensor Positioning

( Yu-sheng Lu ),( Chin-feng Lai ),( Chia-cheng Hu ),( Yueh-min Huang ),( Xiao-hu Ge ) 한국인터넷정보학회 2010 KSII Transactions on Internet and Information Syst Vol.4 No.3

Rapid developments in wireless sensor networks have extended many applications, hence, many studies have developed wireless sensor network positioning systems for indoor environments. Among those systems, the Global Position System (GPS) is unsuitable for indoor environments due to Line-Of-Sight (LOS) limitations, while the wireless sensor network is more suitable, given its advantages of low cost, easy installation, and low energy consumption. Due to the complex settings of indoor environments and the high demands for precision, the implementation of an indoor positioning system is difficult to construct. This study adopts a low-cost positioning method that does not require additional hardware, and uses the received signal strength (RSS) values from the receiver node to estimate the distance between the test objects. Since many objects in indoor environments would attenuate the radio signals and cause errors in estimation distances, knowing the path loss exponent (PLE) in an environment is crucial. However, most studies preset a fixed PLE, and then substitute it into a radio propagation loss model to estimate the distance between the test points; such method would lead to serious errors. To address this problem, this study proposes a Path Loss Exponent Estimation Algorithm, which uses only four beacon nodes to construct a radio propagation loss model for an indoor environment, and is able to provide enhanced positioning precision, accurate positioning services, low cost, and high efficiency.

A novel and efficient procedure for the preparation of 4,40-bis(chloromethyl)biphenyl by chloromethylation of biphenyl catalyzed by PEG1000-DAIL under homogeneous catalysis in aqueous media

Yu Lin Hu,Qiang Ge,Peng Cheng Wang,Ting Ting Lu,Ming Lu 한국공업화학회 2010 Journal of Industrial and Engineering Chemistry Vol.16 No.4

As described in this article, 4,40-bis(chloromethyl)biphenyl was obtained in 85% excellent yield by chloromethylation of biphenyl catalyzed by the recyclable temperature-dependant phase-separation system that comprised the dicationic acidic ionic liquid PEG1000-DAIL and methylcyclohexane under homogeneous catalysis in aqueous media. Compared to other synthetic methods, the novel method not only enhanced the yield, but also made the operating units easy workup. The mechanism of chloromethylation reaction and the process of catalysis in the thermoregulated ionic liquid bi-phase system were proposed.

Image Zooming for Indexed Color Images Based on Bilinear Interpolation

Yu-Chen Hu,Bing-Hwang Su,Wu-Lin Chen,Wan-Yu Lu 보안공학연구지원센터 2012 International Journal of Multimedia and Ubiquitous Vol.7 No.2

Proposal of a Pretreatment Nomogram for Predicting Local Recurrence after Intensity-Modulated Radiation Therapy in T4 Nasopharyngeal Carcinoma: A Retrospective Review of 415 Chinese Patients

Lu-Lu Zhang,Yi-Yang Li,Jiang Hu,Guan-Qun Zhou,Lei Chen,Wen-Fei Li,Ai-Hua Lin,Jun Ma,Zhen-Yu Qi,Ying Sun 대한암학회 2018 Cancer Research and Treatment Vol.50 No.4

Purpose Local relapse-free survival (LRFS) differs widely among patients with T4 category nasopharyngeal carcinoma (NPC). We aimed to build a nomogram incorporating clinicopathological information to predict LRFS in T4 NPC after definitive intensity-modulated radiation therapy (IMRT). Materials and Methods Retrospective study of 415 Chinese patients with non-metastatic T4 NPC treated with definitive IMRT with or without chemotherapy at our cancer center between October 2009 and September 2013. The nomogram for LRFS at 3 and 5 years was generated based on multivariate Cox proportional hazards regression, and validated using bootstrap resampling, assessing discriminative performance using the concordance index (C-index) and determining calibration ability via calibration curves. Results Five-year LRFS was 88.8%. We identified and incorporated four independent prognostic factors for LRFS: ethmoid sinus invasion, primary gross tumor volume, age, and pretreatment body mass index. The C-index of the nomogram for local recurrence was 0.732 (95% confidence interval, 0.726 to 0.738), indicating excellent predictive accuracy. The calibration curve revealed excellent agreement between nomogram-predicted and observed LRFS probabilities. Risk subgroups based on total point score cutoff values enabled effective discrimination of LRFS. Conclusion This pretreatment nomogram enables clinicians to accurately predict LRFS in T4 NPC after definitive IMRT, and could help to facilitate personalized patient counselling and treatment strategies.

Effects of Selenizing Modification on Characteristics and Antioxidant Activities of Inonotus obliquus Polysaccharide

Yang Hu,Shanyi Shi,Lu Lu,Chunying Teng,Sumei Yu,Xin Wang,Min Yu,Jinsong Liang,Juanjuan Qu 한국고분자학회 2017 Macromolecular Research Vol.25 No.3

Excessive reactive oxygen species is implicated in the etiology and pathology of many acute and chronic diseases. Selenium acts as an antioxidant and stimulates the creation of more antioxidants. Selenizing modification polysaccharides potentiate the physiological and pharmacological activities of selenium and polysaccharide. In this study, Inonotus obliquus polysaccharide (IOP) extracted from cultured mycelia was modified into Se-IOP by HNO3- Na2SeO3 method. The characteristics and antioxidant activity of IOP and Se-IOP were comparatively investigated. The result showed that polysaccharide content of purified IOP was 98.9%. The selenium content of Se-IOP was 0.71 mg/g. Both IOP and Se-IOP were homogeneous polysaccharides with a molecular weight of 37.354 and 28.071 kDa, respectively depicted in high performance gel permeation chromatogram (HPGPC). Moreover, both IOP and Se- IOP were composed of Man, Glu, and Gal with a molar ratio of 7.7:32.6:23.3 and 8.3:32.1:22.7, respectively determined by high performance liquid chromatography (HPLC). The characteristic absorption peak of O-Se-O, Se=O and C-O-Se appeared at 1026.75, 772.82, and 652.29 cm-1 respectively in FT-IR spectrum of Se-IOP indicating the success of selenylation. NMR spectrum further confirmed the anomeric carbon signals and chemical shifts in IOP and Se-IOP. These variations induced by selenylation may lead to a higher antioxidant activity of Se-IOP on scavenging hydroxyl, 2,2-diphenyl-1-picryl-hydrazyl (DPPH) and superoxide radical than that of IOP. Furthermore, Se- IOP treatment could also reduce oxidant damage by decreasing the level of malondialdehyde (MDA) and increasing the activities of superoxidedismutase (SOD) and GSH-Px in mice.

An Efficient Synthetic Method for 3,3',4,4'-Biphenyltetracarboxylic Anhydride

Yu Lin Hu,Ming Lu,Xiang Liu,Peng Cheng Wang 대한화학회 2009 Bulletin of the Korean Chemical Society Vol.30 No.9

Association of Lipoprotein-Associated Phospholipase A_2 with Characteristics of Vulnerable Coronary Atherosclerotic Plaques

Yu-Sheng Liu,Qing-Hua Lu,Xiao-Bo Hu,Hong-Zhuan Li,Wei-Dong Jiang,Xin Wang,Hao Lin,Ai-Qiong Qin,Yong-Mei Wang,Tong Zhao,Zhao-Qiang Dong,Mei Zhang 연세대학교의과대학 2011 Yonsei medical journal Vol.52 No.6

Purpose: Lipoprotein-associated phospholipase A2 (Lp-PLA_2) is an inflammatory enzyme expressed in atherosclerotic plaques. We investigated the association of circulating Lp-PLA_2 with characteristics of vulnerable coronary atherosclerotic plaques. Materials and Methods: We recruited 113 patients with either unstable angina (UA, n=59) and stable angina (SA, n=54) by coronary angiography. Thirty-six healthy subjects served as controls. Intravascular ultrasound (IVUS) was used to evaluate the characteristics of coronary atherosclerotic plaque, and serum Lp-PLA2 concentration was measured as well. Results: Lp-PLA_2 concentration was significantly higher in both UA and SA patients [(396±36) μg/L and (321±39) μg/L, respectively]compared with the controls [(127±49) μg/L, p<0.01], and higher in UA than SA group. IVUS findings showed that remodeling index (RI) (0.91±0.15 vs. 0.85±0.11, p=0.005) and eccentricity index (EI) (0.73±0.16 vs. 0.65±0.22, p=0.039) were larger in UA than in SA group, and fibrous caps were thicker in SA than UA group [(0.91±0.23) mm vs. (0.63±0.21) mm, p=0.032]. Moreover, Lp-PLA_2 correlated positively with EI (r=0.439, p<0.01) and RI (r=0.592, p<0.05) in UA group. There was an inverse relationship between Lp-PLA_2 and fibrous cap thickness in both UA (r=-0.587, p<0.001) and SA (r=-0.318, p<0.05) groups. The independent risk factors in UA group were Lp-PLA_2 (OR=1.055, 95% CI: 1.03-1.08, p=0.013), LDL-cholesterol (OR=0.032, 95% CI: 0.00-0.05, p=0.041) and fibrous cap thickness (OR=0.008, 95% CI: 0.00-0.45, p=0.019). Lp-PLA_2 was strongly associated with both EI and fibrous cap thickness in both groups. Conclusion: Serum level of Lp-PLA_2 is associated with both eccentricity index and fibrous cap thickness in both UA and SA groups. Elevated levels of circulating Lp-PLA_2 might to be a strong risk factor and more serious for unstable angina than stable angina.

Synthesis of Some Biologically Active Halogenopurines

Hu, Yu Lin,Liu, Xiang,Lu, Ming,Ge, Qiang,Liu, Xiao Bin Korean Chemical Society 2010 대한화학회지 Vol.54 No.4

A series of some biologically active halogenopurines were synthesized from commercially available guanine (1). The reaction of guanine with acetic anhydride yielded 2,9-diacetylguanine (2-1) by acetylation reaction. Further treatment of 2-1 with $POCl_3$ by PEG-2000 phase transfer catalysis furnished the important compound 3a, then 2-amino-6-halogenopurines (3b-d) were obtained through chlorine-exchange halogenations between KX and 3a by TPPB phase transfer catalyst. Further, 2-halogenopurines (2-2a-d, 4-2a-d, 5a-d) were efficiently prepared from 2-amino-6-substituted purines (1, 3a, 4-1) via a diazotization catalyzed by their corresponding CuX, and some new compounds 2-2a, 2-2c, 2-2d, 4-2c, 4-2d, 5b, 5c and 5d have been discovered. The structures of synthesized compounds were mainly established on the basis of their elemental analysis, $^1H$ NMR, as well as their mass spectral data. All the title compounds were screened for their antifungal activities, and some of the compounds showed promising activity. Guanine (1)으로부터 생물활성이 있는 halogenopurines계 화합물을 합성하였다. Guanine을 acetic anhydride와 반응시켜서 2,9-diacetylguanine (2-1)을 합성하여 얻어진 화합물을 $POCl_3$와 반응시켜서 화합물 3a를 합성하고, 다음 단계에서 2-amino-6-halogenopurines (3b-d)를 합성하였다. 2-Halogenopurines (2-2a-d, 4-2a-d, 5a-d)을 2-amino-6-substituted purines (1, 3a, 4-1)로부터 효율적으로 합성한 후에, 새로운 화합물인 2-2a, 2-2c, 2-2d, 4-2c, 4-2d, 5b, 5c 및 5d를 합성하였다. 합성한 화합물의 구조를 원소분석, $^1H$ NMR, mass spectral data로 확인하였으며, 합성한 화합물에 대한 항균 활성을 시험하였다.

Effects of Plant Nitrogen on Ecological Fitness of the Brown Planthopper, Nilaparvata lugens Stal. in Rice

Lu, Zhong-Xian,Heong, Kong-Luen,Yu, Xiao-Ping,Cui Hu Korean Society of Applied Entomology 2004 Journal of Asia-Pacific Entomology Vol.7 No.1

Ecological fitness characters of the brown planthopper increased proportionally with increase in nitrogen content of rice plants they were bred on. The nymphs survived better and had shorter life spans. Females weighed heavier, laid more eggs and lived longer. In addition, egg hatchability was significantly increased. Number of insects and dry mass from one pair of parents were also significantly higher in high nitrogen plants. Relationships between each of these characters with nitrogen content fitted the linear models well. These characters from insects reared on four successive generations in low, medium and high nitrogen regimes were also investigated. There was little between-generation difference in most characters, except for the population and its dry mass produced by one pairs of insects. This implies that in areas where nitrogen-rich crops are abundant over long periods, ecological fitness of the brown planthoppers are potentially higher and if natural biological control is compromised, the risk of extensive outbreaks are higher. Implications to sudden stoppage of insecticide use in these areas are also discussed.

Performance Analysis of Permanent Magnet Brushless Motors for Mobility Scooters

Yu-Chuan Lu,Ming-Yang Cheng,Chun-Hsien Wu,Wei-Chih Chen,Cheng-Hu Chen 전력전자학회 2011 ICPE(ISPE)논문집 Vol.2011 No.5

Most modern commercial electric scooters are still equipped with the DC brush motor. This type of motor has mechanical structures such as permanent magnet, brush, and commutator. Therefore, it has attractive features, e.g., large start-up torque and easy to control. However, this kind of mechanical commutation often leads to drawbacks such as low power density, low reliability, and poor heat dissipation. In contrast, the Permanent Magnet Brushless Motors (PMBLMs) have advantages such as high efficiency and maintenance free, etc. Hence, the PMBLMs have great potential in becoming the actuators for electric scooters. In this paper, the performance of the PMBLMs with trapezoidal and sinusoidal back-emf waveforms driven by square wave commutation and sinusoidal commutation is investigated. To reduce the cost, low-resolution Hall sensors are used to implement sinusoidal commutation.