Circuit Optimization Method to Reduce Disturbances in Poly-Si 1T-DRAM

A capacitorless one-transistor dynamic random-access memory device (1T-DRAM) is proposed to resolve the scaling problem in conventional one-transistor one-capacitor random-access memory (1T-1C-DRAM). Most studies on 1T-DRAM focus on device-level operation to replace 1T-1C-DRAM. To utilize 1T-DRAM as a memory device, we must understand its circuit-level operation, in addition to its device-level operation. Therefore, we studied the memory performance depending on device location in an array circuit and the circuit configuration by using the 1T-DRAM structure reported in the literature. The simulation results show various disturbances and their effects on memory performance. These disturbances occurred because the voltages applied to each device during circuit operation are different. We analyzed the voltage that should be applied to each voltage line in the circuit to minimize device disturbance and determine the optimized bias condition and circuit structure to achieve a large sensing margin and realize operation as a memory device. The results indicate that the memory performance improves when the circuit has a source line and the bias conditions of the devices differ depending on the write data at the selected device cell. Therefore, the sensing margin of the 1T-DRAM used herein can expectedly be improved by applying the proposed source line (SL) structure.

The Estimation of Seismic Site Amplification of Bukittinggi City, West Sumatera, Indonesia

Bukittinggi city area is exposed substantial risk of both, close to seismic source line and site amplification due to soft surface sediment / soil layer. The Great Sumateran Fault (GSF) which is crossing this area, notorious as a very active seismic source. Its responsible to some major earthquake in the vicinity of the fault line. Generally, Bukittinggi area is covered by volcanic product as pumiceous tuff. We applied combined array and single station microtremor measurement to characterize near surface sediment in this area. Based on analysis microtremor single station and array using spatial autocorrelation (SPAC) method, weathered surface layer thickness is in the range of 0-108 m with shear wave velocity in the range of 62-190 m/s, while the fresh pumiceous tuff is in the range of 375-629 m/s. The estimation of site amplification in this area which is indicated by mean amplification is in the range of 1-1.95. The high amplification zone is occupies the northernmost area and some area locally in the southern part of Bukittinggi city.

Area Optimization Techniques for High-Density Spin-Orbit Torque MRAMs

This paper presents area optimization techniques for high-density spin-orbit torque magnetic random-access memories (SOT-MRAMs). Although SOT-MRAM has many desirable features of nonvolatility, high reliability and low write energy, it poses challenges to high-density memory implementation because of the use of two access transistors per cell. We first analyze the layout of the conventional SOT-MRAM bit-cell that includes two vertical metal lines, a bit-line and a source-line, limiting the horizontal dimension. We further propose two design techniques to reduce the horizontal dimension by decreasing the number of metal lines per cell without any performance overhead. Based on the fact that adjacent columns in a bit-interleaved array are not simultaneously accessed, the proposed techniques share a single source-line between two consecutive bit-cells in the same row. The simulation result shows that proposed techniques can achieve a bit-cell area reduction of 10–25% compared to the conventional SOT-MRAM. The comparison of our proposed designs with the standard spin-transfer torque MRAM shows 45% lower write energy, 84% lower read energy, and 2.3 × higher read-disturb margin.

Energy Harvesting for Wireless Sensor Nodes Using Rectenna

Wireless sensor nodes generally operate using energy from source line batteries, which need to be replaced or recharge from time to time. The connection of electromagnetic energy to DC energy, which is called radiofrequency (RF) energy harvesting, is one of the best techniques to act as an energy source for this equipment. An ambient amount of RF energy is present in our environment radiated from numerous sources so that it can act as a much predictable source of energy as compared to other techniques of energy harvesting. This system eliminates the periodic replacement of energy batteries for these sensor nodes. Despite the enormous RF energy present in the environment, the power per unit area is quite low. Hence, the major barrier is to increase the output of the rectifier circuit, even though the power density is low.

Thermoelastic Processes by a Continuous Heat Source Line in an Infinite Solid via Moore–Gibson–Thompson Thermoelasticity

Many attempts have been made to investigate the classical heat transfer of Fourier, and a number of improvements have been implemented. In this work, we consider a novel thermoelasticity model based on the Moore–Gibson–Thompson equation in cases where some of these models fail to be positive. This thermomechanical model has been constructed in combination with a hyperbolic partial differential equation for the variation of the displacement field and a parabolic differential equation for the temperature increment. The presented model is applied to investigate the wave propagation in an isotropic and infinite body subjected to a continuous thermal line source. To solve this problem, together with Laplace and Hankel transform methods, the potential function approach has been used. Laplace and Hankel inverse transformations are used to find solutions to different physical fields in the space–time domain. The problem is validated by calculating the numerical calculations of the physical fields for a given material. The numerical and theoretical results of other thermoelastic models have been compared with those described previously.

Evaluation of possible corrosion enhancement due to telluric currents: case study of the Bolivia–Brazil pipeline

The electric field induced in the Bolivia–Brazil gas pipeline (GASBOL) was calculated by using the distributed source line transmission (DSLT) theory during several space weather events. We used geomagnetic data collected by a fluxgate magnetometer located at São José dos Campos (23.2∘ S, 45.9∘ W). The total corrosion rate was calculated by using the Gummow (2002) methodology and was based on the assumption of a 1 cm hole in the coating of the pipeline. The calculations were performed at the ends of pipeline where the largest “out-of-phase” pipe-to-soil potential (PSP) variations were obtained. The variations in PSP during the 17 March 2015 geomagnetic storm have led to the greatest corrosion rate of the analyzed events. All the space weather events evaluated with high terminating impedance may have contributed to increases in the corrosion process. The applied technique can be used to evaluate the corrosion rate due to the high telluric activity associated with the geomagnetic storms at specific locations.

Effect of Word-Line Bias on Linearity of Multi-Level Conductance Steps for Multi-Layer Neural Networks Based on NAND Flash Cells

NAND flash memory which is mature technology has great advantage in high density and great storage capacity per chip because cells are connected in series between a bit-line and a source-line. Therefore, NAND flash cell can be used as a synaptic device which is very useful for a high-density synaptic array. In this paper, the effect of the word-line bias on the linearity of multi-level conductance steps of the NAND flash cell is investigated. A 3-layer perceptron network (784×200×10) is trained by a suitable weight update method for NAND flash memory using MNIST data set. The linearity of multi-level conductance steps is improved as the word line bias increases from Vth −0.5 to Vth +1 at a fixed bit-line bias of 0.2 V. As a result, the learning accuracy is improved as the word-line bias increases from Vth −0.5 to Vth+1.

ANALISIS FAKTOR-FAKTOR MEMPENGARUHI KEPUASAN KERJA KARYAWAN PADA PT. ASTRA CABANG MEDAN

The purpose of this study is to analyze the factors that influence employee job satisfaction at PT Astra Medan Branch. The benefits of research help provide input to the leadership of the company in determining policies for the progress of PT Astra Medan Branch and can be used as reference material in enriching and deepening science. The number of samples was 105 respondents, the types of data used were primary and secondary data, and the method of data collection through questionnaires and documentation, the method of data analysis used factor analysis. The results showed that the KMO Measure of Sampling Adequacy (MSA) figure of 0.825 was above 0.50, with a significance of 0,000, so the variables were worthy of further analysis. Scree plot shows the graph, where from factor 1 to factor 2 (source line component number = 1 to 2), the direction of the line decreases sharply. Then from number 2 to number 6, the direction of the line is still decreasing with slope getting smaller. The seventh to twenty-first factors are below the number of the Y axis (eigenvalues). This shows that the six factors are best for summarizing the twenty-one factors that influence employee job satisfaction at PT Astra Medan Branch. The dominant factors affecting job satisfaction of employees of PT Astra Medan Branch are incentives or bonuses, work policies and procedures, promotion of positions, intrinsic of work, social security and official vehicles. The most dominant factor influencing employee job satisfaction is incentives or bonuses. Suggestions that are recommended to company leaders should the company increase the amount of incentives or bonuses, pay attention to the establishment of work policies and procedures, maintain the provision of social security and official vehicles. The company should provide the greatest opportunities for employees with the best performance to be promoted to higher positions.

The Effect of Light Source Line Width on the Spectrum Resolution of Dual-Frequency Coherent Detection Signals

In this paper, the power spectrum resolution problem of dual-frequency coherent mixing signals is analyzed when the Doppler frequency difference is small. The power spectrum function formula of the four optical coherent mixing signals is obtained using statistical theory and the Wiener–Khinchin theorem. The influence of delay time and light source line width on the power spectrum of dual-frequency coherent signals is analyzed using this formula. The results show that delay time only affects the peak of the power spectrum of the coherent signal. An increase in the line width of the light source broadens the signal power spectrum and reduces the peak value. The necessary condition for distinguishing the Doppler frequency difference is that the theoretical Doppler frequency difference is greater than 1/5 times the line width of the light source.