TDOA-Based and RSSI-Based Underground Wireless Positioning Methods and Performance Analysis

Guofang Dong,Bin Yang 보안공학연구지원센터 2015 International Journal of Future Generation Communi Vol.8 No.5

Wireless location has become one of the important technologies of wireless sensor network application. Due to the underground wireless location affected by various factors, the positioning system cannot meet the actual demand. In this paper, Time Difference of Arrival (TDOA) and Received Signal Strength Indicator (RSSI) location technologies have been investigated, then various impact factors on the TDOA and RSSI location systems have been discussed, multipath channel, different shapes of the roadway on the propagation loss. In order to reduce the error, estimation error has been correlated and compensated. Simulations show that the proposed system consistently outperforms other existing localization methods and can achieve higher accuracy.

Convergence Properties of a Correlative Polak-Ribiacuteere Conjugate Gradient Method

Guofang Hu,Biao Qu 한국전산응용수학회 2006 Journal of applied mathematics & informatics Vol.22 No.1-2

In this paper, an algorithm with a new Armijo-type line search is proposed that ensure global convergence of a correlative Polak-Ribi´ere conjugate method for the unconstrained minimization of non-convex differentiable function.

Other People’s Success: Impact of the “Model Minority” Myth on Underachieving Asian Students in North America

Guofang Li 한국교육개발원 2005 KEDI Journal of Educational Policy Vol.2 No.1

This paper revisits the “model minority” myth and examines how it has become a “destructive myth” for those underachieving Asian children who do not fit the stereotypes. It argues that contemporary “model minority” images promote invisibility and disguise the social realities of many Asian students who are not successful. Therefore, these images are false representations of many Asian students and have posed as a threat to their educational advancement. To further demythologize the “model minority” myth, this paper reveals the academic difficulties of a Chinese student who lived under the shadow of other children’s success. The case study demonstrates that among other factors, the “model minority” images contribute to Asian students’ underachievement. The stereotypes have enhanced mainstream school’s “blaming the victims” approach toward underachieving Asian students; and have heightened Asian parents’ “education fever.” The analysis suggests that more attention needs to be paid to the individual lived experiences of these struggling learners to facilitate their academic success.

CONVERGENCE PROPERTIES OF A CORRELATIVE POLAK-RIBIERE CONJUGATE GRADIENT METHOD

Hu, Guofang,Qu, Biao 한국전산응용수학회 2006 Journal of applied mathematics & informatics Vol.22 No.1

In this paper, an algorithm with a new Armijo-type line search is proposed that ensure global convergence of a correlative Polak-Ribiere conjugate method for the unconstrained minimization of non-convex differentiable function.

Backstepping Based Trajectory Tracking Control of a TBM Steel Arch Splicing Manipulator

Yuxi Chen,Guofang Gong,Xinghai Zhou,Yakun Zhang,Weiqiang Wu 제어·로봇·시스템학회 2024 International Journal of Control, Automation, and Vol.22 No.2

At present, the splicing of steel arches for open-type TBM suffers from the problems of labor-intensive, time-consuming, low efficiency and greater potencial risk to workers. Rock-fall and collapse caused by untimely support is still one of the main construction accidents. In this paper, a novel steel arch splicing manipulator is developed for unmanned and automated steel arch splicing, and a backstepping method based cascade control strategy is proposed to improve the trajectory tracking control performance. Firstly, the inner-loop controller is designed to compensate the flow coupling between each joint-driven hydraulic cylinder based on dynamic analysis and feedback linearization. Secondly, the adaptive robust controller is adopted for outer-loop controller design to deal with parametric uncertainties and external disturbances. Finally, the system stability is proved by Lyapunov function, then comparative experiments are conducted to verify the effectiveness and superiority of the proposed control scheme. It can be concluded that the proposed controller has a better trajectory tracking control performance, while the control input is much smoother than that of traditional PID controller.

A Pilot Randomized Clinical Study of the Additive Treatment Effect of Photodynamic Therapy in Breast Cancer Patients with Chest Wall Recurrence

Yan Liu,Guofang Hou,Xiaobei Zhang,Jing Jing Liu,Sheng Zhang,Jin Zhang 한국유방암학회 2014 Journal of breast cancer Vol.17 No.2

Purpose: This study investigated the additive effect of photodynamictherapy (PDT) plus traditional radiotherapy (RT) for patientswith breast cancer and chest wall recurrence. Methods: Atotal of 40 patients with recurrent breast cancer were prospectivelyrandomized to receive RT alone (group A, n=20) or PDTand RT in combination (group B, n=20). Traditional RT at a doseof 50 Gy was delivered in 25 fractions with or without exposureto 5-aminolevulinic acid and red light as PDT. Results: The responserates were not statistically different between the groups,but more patients achieved a complete response (CR) in groupB (50%) than in group A (20%). The median time to CR in groupB was significantly shorter than that in group A (109.6 days vs. 175.2 days, p=0.001). Adverse event profiles were not differentbetween the groups. Conclusion: An additive antitumor effect isdemonstrated with additional PDT to RT. This combination therapymight reduce the duration of exposure to RT, but further investigationis warranted.

Alkylation of anthracene to 2-isopropylanthracene catalyzed by Lewis acid ionic liquids

Min Chen,Ying Luo,Guofang Li,Minqiang He,Jimin Xie,Huamin Li,Xinhua Yuan 한국화학공학회 2009 Korean Journal of Chemical Engineering Vol.26 No.6

Alkylation of anthracene with 2-chloropropane to 2-isopropylanthracene catalyzed by various Lewis acidic ionic liquids (ILs), such as [Emim]Cl-AlCl3, [Emim]Cl-FeCl3, [Emim]Cl-ZnCl2, [Bmim]Cl-AlCl3, and [Omim]Cl-AlCl3 ([Emim]+=1-ethyl-3-methylimidazolium cation, [Bmim]+=1-butyl-3-methylimidazolium cation, [Omim]+=1-octyl-3- methylimidazolium cation,), was investigated. [Emim]C1-A1C13 ionic liquid was found to be the most active catalyst in the alkylation. The yield of 2-isopropylanthracene was up to 74.5% and the selectivity of 2-isopropylanthracene was up to 82.9%. The [Emim]C1-A1C13 ionic liquid catalyst showed good catalytic activity after running for 6 times. Ease of product separation and the recycling performance of the ionic liquid catalyst is expected to contribute to the development of clean and environmentally friendly strategy for the synthesis of 2-isopropylanthracene.

The effectiveness and efficiency of China’s special admission policies: the case of X University

Sunny Xinchun Niu,Guofang Wan 서울대학교 교육연구소 2018 Asia Pacific Education Review Vol.19 No.1

The Chinese government has implemented a series of special admission policies in recent years to increase access to elite universities for disadvantaged students from rural areas and less developed inland regions. Using administrative data of 1996–2015 freshman cohorts and survey data of a 2014 freshman cohort at X University in the eastern China, we empirically assess the effectiveness, and the dual concerns of equity and efficiency of these policies. Findings show that these policies have effectively changed the geographic composition of enrollees at X University toward higher proportions of students from the central and western regions and lower share of the local students. While students from the western region underperformed academically, urban students in this region caught up quickly. Low family SES and weak academic preparation largely explained why rural students from the western region underperformed. Importantly, compared with the local students who scored lower in college entrance exam—the proxy for likely displaced students because of the policies, the likely admission policy beneficiaries performed about equally well. These results indicate that the current practice of Chinese special admission policies has effectively promoted equal access to Chinese elite universities with a limited loss in efficiency.

Macro-Micro Mechanical Behavior of Crushable Granular Materials under Generalized Stress Conditions

Yiming Liu,Chenming Xu,Guofang Xu,Haijun Mao,Zunqun Xiao 대한토목학회 2021 KSCE JOURNAL OF CIVIL ENGINEERING Vol.25 No.5

This paper investigated the joint influence of particle crushing and intermediate principal stress coefficient on the macro and micro performances of granular assembles by using 3D discrete element method. The soil particle was modeled by crushable agglomerate. Numerical true triaxial tests with crushable agglomerates were performed. The mechanical behaviors of specimens with unbreakable agglomerates were also tested in this study. The results demonstrated that grain breakage can significantly affect the behaviors of granular soils in both macro and micro scales. Moreover, the present paper also showed that particle breakage did not influence the unique relationship between the intermediate principal stress coefficient band the deviatoric fabric of strong contacts. This can provide a good basis for developing micro-parameter-based constitutive model considering particle breakage for granular soils.

Strategies to Extend Thrombolytic Time Window for Ischemic Stroke Treatment: An Unmet Clinical Need

Ike dela Peña,Cesar Borlongan,Guofang Shen,Willie Davis 대한뇌졸중학회 2017 Journal of stroke Vol.19 No.1

To date, reperfusion with tissue plasminogen activator (tPA) remains the gold standard treatment for ischemic stroke. However, when tPA is given beyond 4.5 hours of stroke onset, deleterious effects of the drug ensue, especially, hemorrhagic transformation (HT), which causes the most significant morbidity and mortality in stroke patients. An important clinical problem at hand is to develop strategies that will enhance the therapeutic time window for tPA therapy and reduce the adverse effects (especially HT) of delayed tPA treatment. We reviewed the pharmacological agents which reduced the risk of HT associated with delayed (beyond 4.5 hours post-stroke) tPA treatment in preclinical studies, which we classified into those that putatively preserve the blood-brain barrier (e.g., minocycline, cilostazol, fasudil, candesartan, and bryostatin) and/or enhance vascularization and protect the cerebrovasculature (e.g., coumarin derivate IMM-H004 and granulocyte colony-stimulating factor). Recently, other new therapeutic modalities (e.g., oxygen transporters) have been reported which improved delayed tPA-associated outcomes by acting through other mechanisms. While the above-mentioned interventions unequivocally reduced delayed tPA-induced HT in stroke models, the long-term efficacy of these drugs are not yet established. Further optimization is required to expedite their future clinical application. The findings from this review indicate the need to explore the most ideal adjunctive interventions that will not only reduce delayed tPA–induced HT, but also preserve neurovascular functions. While waiting for the next breakthrough drug in acute stroke treatment, it is equally important to allocate considerable effort to find approaches to address the limitations of the only FDA-approved stroke therapy.