Bui Thu Lam, Le Quy Don Technical University
Deputy Editor-In-Chief
Tran Xuan Nam, Le Quy Don Technical University
Advisory Member
Pham The Long, Le Quy Don Technical University
Nguyen Binh, Posts and Telecommunications Institute of Technology
Dinh The Cuong, Directorate of Information Technology
Luong Chi Mai, Vietnam Academy of Science and Technology
Huynh Quyet Thang, Hanoi University of Science and Technology
Nguyen Huu Thanh, Hanoi University of Science and Technology
Vu Duc Thi, Vietnam National University, Hanoi
Nguyen Thanh Thuy, Vietnam National University, Hanoi
Dao Thanh Tinh, Le Quy Don Technical University
Scientific Secretary
Nguyen Van Giang, Le Quy Don Technical University
Table: Issue 7
ID Paper
[Pdf link]
Fitting spherical objects in 3-D point cloud using the geometrical constraints.
Le Van Hung, Vu Hai, Nguyen Thi Thuy, Le Thi Lan, Tran Thi Thanh Hai
Estimating parameters of a primitive shape from a 3-D point cloud usually meets difficulties due to noises of data require a huge amount of computational time. The real point cloud of objects in the 3D environment have many noise and may be obscured when they are captured from Kinect version 1. In this paper, we utilize and analyse of spherical estimation steps from the point cloud data in Schnabel et al. \cite{Schnabel2007}. From this, we propose a geometrical constraint to search 'good' samples for estimating spherical model and then apply to a new robust estimator named GCSAC (Geometrical Constraint SAmple Consensus). The proposed GCSAC algorithm takes into account geometrical constraints to construct qualified samples. Instead of randomly drawing minimal subset sample, we observe that explicit geometrical constraint of spherical model could drive sampling procedures. At each iteration of GCSAC, the minimal subset sample is selected by two criteria (1) They ensure consistency with the estimated model via a roughly inlier ratio evaluation; (2) The samples satisfy geometrical constraints of the interested objects. Based on the qualified samples, model estimation and verification procedures of a robust estimator are deployed in GCSAC. Comparing with the common robust estimators of RANSAC family (RANSAC, PROSAC, MLESAC, MSAC, LO-RANSAC and NAPSAC), GCSAC overperforms in term of both precisions of the estimated model and computational time. The implementations and evaluation datasets of the proposed method are made publicly available.
A type system for inferring the log memory of transactional program from shared variables.
Nguyen Ngoc Khai, Truong Anh Hoang.
In previous works, we built a type system for calculating the maximum resource usage of a transactional program. However, this resource was calculated based on the parameters. These parameters were the resources that transactions need to use and calculated manually based on analysis source code of program by the programmer. Therefore, the result was still methodical and semi-automatic leading to inconvenient to be used for programmers. In this work, we have improved the type system with fully automatic functions for inferring the maximum resources usage of transactional programs. Based on this result, the programmers do not need to calculate manually parameters like previous work. The resources here are specified into the log memory of the transaction. In order to do this, the language is also improved, complementary, and it is closer to the actual language.
A retrial queueing model in WLAN networks with the fractional guard channel policy.
Dang Thanh Chuong, Hoa Ly Cuong.
In wireless networks, the protection of handover calls for seamless wireless services are considered. For this reason, we propose a novel queueing model with impatient customers for 3G-WLAN integrated networks applying the Fractional Guard Channel (FGC) admission control policy and approximated by the HM2 algorithm. Moreover, the comparision between two types of the FGC policy can be used to evaluate the performance of the system.
Outage probability evaluation of underlay cognitive radio networks under joint impact of channel correlation and hardware impairments.
Pham Thi Dan Ngoc, Tran Trung Duy, Ho Van Khuong
In this paper, we evaluate outage performance of underlay cognitive radio networks under joint impact of channel correlation and hardware impairment. In the secondary network of the proposed system model, a secondary source transmits its signal to a secondary destination which is equipped with two antennas, and uses selection combining technique to combine the received signals. Before transmitting its signal, the secondary source must adapt its transmit power to satisfy the interference power constraint required by multiple primary users. For performance evaluation, we derive an exact closed-form expression of outage probability over Rayleigh fading channels. Our derived expressions are verified by Monte Carlo simulations.
Fine grained clock gating technique for reducing dynamic power loss in Ping Pong game application.
Vo Minh Huan.
The paper proposed the fine-grained clock gating concept in subblock level instead of conventional block level to implement low power ping-pong game SoC on DE2-115 FPGA board. Because not all subblocks are idle simultaneously to implementing clock gating at conventional block level, a few subblocks may be idle, others may still be active in operation system. By doing fine-grain clock gating in subblock level, we can save more dynamic power consumption. The proposed system is stable and saved up to 58%, 53%, 48%, 24%, 13% compared to no-clock gating technique, and 53%, 48%, 44%, 21%, 12% compared to normal clock gating at frequency operation of 5GHz, 1GHz, 0.5GHz, 50MHz, 5MHz in term of total power consumption. The proposed fine-grained design has 49 logic element overhead compared to coarse grained clock gating technique but it is quite small compared to total used logic gate.