275 research outputs found
Recommended from our members
Design for Ultra Low Power Hardware Accelerator Using Approximate and In-Memory Computing
No full textIn recent years, the rapid slowdown of Moore's Law has made it impossible to enhance processor performance at the same rate by merely scaling down transistor size. Simultaneously, the volume of data processed by computing systems has surged, making the memory wall a significant bottleneck for artificial intelligence (AI) and digital signal processing (DSP) accelerators. Data-intensive computing tasks such as AI and DSP have led to a dramatic rise in energy demands for computing, far outpacing the linear growth of global energy production. Consequently, alternative memory-computing paradigms beyond the Von Neumann architecture, along with low-power and hardware-efficient computing approaches enabled by approximation, are gaining popularity, especially for emerging AI and media applications that can tolerate higher error rates. In this thesis, we try to address the power efficiency of the hardware accelerator designs. First, we propose an efficient hybrid parallel Processing-in-Memory (PIM)-based computation for the Discrete Hadamard Transform (DHT). Our method leverages the recursive computation of DHT using memristor-aided logic (MAGIC) gates, where arithmetic operations are performed via simple logic NOR operations. Second, to further reduce power consumption, and improve computing throughput, we develop a novel multi-level reconfigurable approximate logarithmic multiplier design named Multi-ALM. The Multi-ALM is based on a new iterative formulation of approximate logarithmic multiplication, which is mathematically proven and similar to a Taylor series, to balance accuracy and performance/power. This design offers a new way to trade-off accuracy for power/performance in a systematic and progressive manner. Last but not least, we propose a new hybrid temporal computing framework that combines pulse rate and temporal data encoding for ultra-low energy hardware accelerators. Our approach is inspired by recent advances in temporal computing or race logic, where data values are encoded as single delays, resulting in significantly lower energy consumption due to minimized single switching events
Recommended from our members
Towards Addressing Thermal and Reliability Challenges in Nanometer Integrated Circuits
No full textOn-chip power densities continue to increase in modern integrated circuits (IC) due to rapid integration and feature scaling.As a consequence, today's high-performance processors have become more thermally constrained than ever before. Increase in temperature has been shown to exponentially degrade reliability of semiconductor chips and has consequently become one of the leading concerns in the industry today. In this thesis, we present our findings and share our contributions from our research efforts in the areas of pre-silicon IC reliability analysis, post-silicon thermal estimation, and advanced microprocessor cooling. Specifically, the first segment of this manuscript will focus on a novel structure-based approach to accelerating electromigration (EM) wear-out for the purposes of post-silicon qualification and burn-in testing. The proposed approach achieves time-to-failure acceleration comparable to the existing current and temperature based stressing techniques at close to nominal operating conditions. Temperature and reliability go hand-in-hand; hence monitoring and managing the processor's temperature while it is in use is equally important in order to maximize performance while minimizing reliability impacts. Therefore, the second segment of this thesis will present our data-driven post-silicon approach to estimating the spatial temperature distribution across the surface of the die in real time. This approach leverages the latest advancements in recurrent-neural-networks for time-series estimation. The estimated temperatures from the proposed model can then be used to supplement the temperature information sensed from the embedded thermal sensors in order to make better informed thermal and reliability regulation decisions. Lastly, the third segment of this thesis will focus on leveraging the aforementioned real-time temperature estimation technique and the emerging thermo-electric based active cooling technologies to propose an on-demand targeted cooling system for modern high-performance processors. This approach yields the sub-ambient cooling benefits of thermo-electric cooling with lower power overheads
Recent advance in computational prototyping for analysis of high-performance analog/RF ICs
No full textA survey of RLCK reduction and simulation methods by fast truncated balanced realization
No full textZingiber calcicola Y. H. Tan & H. B. Ding 2021, sp. nov.
No full textZingiber calcicola Y.H.Tan & H.B.Ding, sp. nov. (Figs. 1–2) Diagnosis: — Zingiber calcicola is similar to Z. nitens Newman (2015: 124) in having terminal inflorescence and similar labellum, but differs by its prominently plicate lamina, oblong (vs. triangular) and longer lateral staminodes (1.3–1.6 cm long vs. 0.2–0.6 cm long), elliptic lamina with the size of 13–19 × 4–6.5 cm (vs. narrowly elliptic lamina with the size of 18–25 × 2–3 cm) and dwarf habit (40–55 cm tall vs. 65–100 cm tall). Type: — CHINA. Yunnan Province: Mengla County, Huiwa village, 21°52′26″ N, 101°27′05″ E, elevation 805 m, 4 September 2020, H.B . Ding & X.D. Zeng T0566 (holotype: HITBC0057379!, isotype: HITBC0057382!). Perennial rhizomatous herbs, 40–55 cm tall, forming a loose clump, with 2–11 leafy shoots. Rhizomes to 3 cm in diam., horizontally elongated and creeping, yellowish brown (fresh rhizomes) to fuscous (drying rhizomes). Leafy shoots slender, with 6–11 leaves, basal ca. 1/3 part of pseudostem leafless; bladeless sheaths 1–3, reddish green, glabrous; leaf sheaths green, pubescent along the margin. Ligules 3–5 mm long, pubescent along the margin, apex truncate or emarginate; petiole 3–15 mm long, glabrous; lamina elliptic, 13–19 × 4–6.5 cm, apex acuminate to caudate, base obtuse, adaxially dark green and glabrous, abaxially pale green and glabrous, prominently plicate. Inflorescence terminal on leafy shoots, in upright position, peduncle sessile, spike cylindrical to fusiform, 5–8 cm long, ca. 1 cm broad, consisting of 4–8 bracts; bracts green, 2.5–3.8 × 1.3–2.0 cm, elliptic, glabrous, apex rounded, enclosing 2 flowers at the basal 3 bracts, 1 flower at the other upper bracts (occasionally only 1 flower in all bracts); bracteoles narrowly lanceolate, 1–1.7 cm long, involute, 0.4–0.6 cm wide when flattened, translucent green to white, glabrous, apex acute to obtuse. Flowers 6–6.5 cm long, much exserted beyond the bracts; calyx tubular, 1.8–2.2 cm long, ca. 3 mm in diam. at base, slightly swollen in the middle, ca. 4 mm in diam., membranaceous, semi-translucent cream-white, glabrous, with unilateral incision to 1 mm deep, with 3 teeth at apex; floral tube slender, 3.2–3.5 cm long, shallowly curved, widening gradually towards apex, cream-white and glabrous at base, brownish yellow and glabrous towards the apical part; dorsal corolla lobe lanceolate, 2.3–2.5 × 0.5–0.8 cm, yellow with semi-translucent veins, glabrous, apex attenuate; lateral corolla lobes narrowly oblong, 2.0–2.2 × 0.3–0.4 cm, yellow with semi-translucent veins, glabrous, apex attenuate; labellum oblong, 1.9–2.3 × 0.8–1.0 cm, adaxially dark maroon with small yellow dots and yellow patch in throat, with yellow stripes from base to center; abaxially yellow; glabrous, margins slightly deflexed, apex emarginate for 2 mm; lateral staminodes oblong, 1.3–1.6 × 0.2–0.3 cm, almost free from labellum, adaxially dark maroon with small yellow dots, abaxially yellow, glabrous, apex obtuse. Stamen 2.2–2.5 cm long with anther crest stretched, filament ca. 2 mm long, yellow, anther ca. 1.2 cm long (excluding anther crest) by ca. 3 mm broad, connective tissue yellow, glabrous; anther thecae ca. 1.2 cm long, dehiscing throughout entire length, pollen yellow; anther crest beak-shaped, 9–11 mm long when stretches, dark maroon with small yellow dots. Style filiform, creamwhite at base, pale yellow and thicken towards apex, glabrous; stigma extending to the tip of anther crest, funnelshaped, pale yellow, ostiole ciliate. Ovary cylindrical, slightly swollen in middle, trilocular, 3–4 × 3–4 mm, yellowish green, glabrous; epigynous glands two, linear, 4–6 mm long, pale yellow. Fruit ovoid to obovoid, 1.4–1.6 × 1–1.2 cm, with persistent calyx, pericarp semi-translucent, yellowish cream and red inside. Seeds ellipsoid, 4–5 × 3–4 mm, black, enveloped by the aril. Aril white, deep denticulate at apex, enveloping 1/3 of the length of the seeds. Phenology: —Flowering from August to September, fruiting from September to October. Distribution and habitat: — Zingiber calcicola is currently known only from its type locality, Mengla County, Yunnan, China. It grows on humus among rocks in tropical seasonal rain forest on limestone hills. Etymology: —The specific epithet ‘ calcicola ’, refers to the habitat in which the species occurs. Conservation status: —So far, Zingiber calcicola is currently known only from the type locality in south Yunnan. Although the habitat is under protected in mini nature reserve, but only one population with less than 500 mature individuals has been found, and the extent of occurrence (EOO) is less than 40 km 2, so we propose to classify it as ‘Critically Endangered’ (CR B1ab(iii,v)) (IUCN Standards and Petitions Committee 2019). Specimens examined (paratypes):— CHINA. Yunnan Province: Mengla County, Huiwa village, 21°52′26″ N, 101°27′08″ E, elevation 774 m, 4 September 2020, H.B . Ding & X.D. Zeng T0565 (HITBC); ibid., 21°52′31″ N, 101°27′00″ E, elevation 717 m, 4 September 2020, H.B . Ding & X.D. Zeng T0567 (HITBC); ibid., 21°52′27″ N, 101°27′07″ E, elevation 787 m, 6 September 2020, H.B . Ding & X.D. Zeng T0568 (HITBC, PE, KUN); ibid., 21°52′32.39″ N, 101°27′31.40″ E, elevation 856 m, 16 August 2021, H.B . Ding, B. Yang & X.D. Zeng T0951 (HITBC); ibid., 21°52′37.24″ N, 101°27′42.21″ E, elevation 717 m, 16 August 2021, H.B . Ding, B. Yang & X.D. Zeng T0952 (HITBC). Notes: Zingiber calcicola belongs to sect. Dymczewiczia due to the terminal inflorescence on the leafy shoot. It is also similar to Z. plicatum Škorničk. & Q.B.Nguy ễn in Leong-Škorničková et al. (2015: 211) and Z. sirindhorniae Triboun & Keeratikiet (2016: 2) in having terminal inflorescence and the limestone habitat, but it differs from the first in its smaller terminal inflorescence (5–8 × ca. 1 cm vs. 12–18 × 1.5–2.0 cm), yellow corolla lobes (vs. cream-white to pale yellow) and dark maroon labellum dotted with small yellow dots (vs. peach-purple to purple, with cream white or pale yellow lines). It differs from the second by its prominently plicate lamina (vs. non-plicate), truncate or emarginate ligule (vs. bilobed) and yellow corolla lobes (vs. white).Published as part of Ding, Hong-Bo, Quan, Dong-Li, Zeng, Xiao-Dong, Li, Jian-Wu & Tan, Yun-Hong, 2021, Zingiber calcicola (Zingiberaceae), a new species from a limestone area in south Yunnan, China, pp. 65-69 in Phytotaxa 525 (1) on pages 65-68, DOI: 10.11646/phytotaxa.525.1.8, http://zenodo.org/record/568185
Gold Coated Tungsten Tips for Scanning Tunneling Microscopy
No full textThis article may be downloaded for personal use only. Any other use requires prior permission of the author and AIP Publishing. This article appeared in Review of Scientific Instruments and may be found at https://doi.org/10.1063/1.1144069.Electrochemically etched tungsten scanning tunneling microscope (STM) tips are dc sputter coated with 20 nm of gold (0.04 rim/s and 10 mTorr of argon). Transmission electron microscope (TEM) images of typical etched tips and gold-coated etched tips are presented. The gold layer forms as a series of spherical sections having a mean height of 6.7 nm and mean width of 19.6 nm. STM images are reported for the uncoated W tips, and for gold-coated graphite after coating the tip with gold. We also provide scanning electron microscopy (SEM) and STM images of the surface of a thin CuTCNQ film. The STM image taken with a gold-coated W tip compares very well to the SEM image of the same sample. Gold coating provides a relatively inexpensive and easy way to produce chemically stable tips of well known electronic structure for use in ambient atmosphere STM studies of morphology (structures ) 10 nm) where atomic resolution is not required.G.A. Fried, X.D. Wang, and K.W. Hipps. (1993). Gold Coated Tungsten Tips for Scanning Tunneling Microscopy. Review of Scientific Instruments. 64. 1495-1501
Model-based optimisation of sustainable biological nutrient removal processes
No full textApplied Science
Begonia mariachristinae Wahlsteen 2018
No full textBegonia mariachristinae Wahlsteen (2018: 161). Type:— MYANMAR. Kachin State: between 27.680652 –27.714888 N, 97.392283–97.396161E, 550–613 m, 7 November 2016, specimens pressed from cultivated plants on 24 November 2017, E. Wahlsteen EW16003 (holotype LD). = Begonia chenii Maw et al. (2020: 204) syn.nov. Type:— MYANMAR. Kachin State: Putao District, on the way from Putao to Upper Shankhaung, in tropical rain forest, 27°25’36.87”N, 97°16’13.56”E, 512 m, 4 May 2017, Y.H. Tan, B. Yang, H.B. Ding, X.D. Zeng, M.B. Maw & T.S. Tin M1378 (holotype HITBC; isotype RAF). Distribution and ecology:— The species is distributed in Putao District, Kachin State, Myanmar. It grows in the shaded environment of rainforest, alt. around 500 m. Flowering is from April to May and fruiting is from May to June. Specimens examined:— MYANMAR. Kachin State: Putao District: Upper Shankhaung, in tropical montane forest, 27°25’36.87”N, 97°16’13.56”E, 512 m, 4 May 2017, Y.H. Tan, B. Yang, H.B. Ding, X.D. Zeng, M.B. Maw & T.S. Tin M1379 (HITBC); Upper Shankhaung, 27°25’35”N, 97°16’14”E, 500 m, 29 April 2016, Y.H. Tan & S.S. Zhou M201627 (HITBC); Upper Shankhaung, 27°25’34”N, 97°16’13”E, 520 m, 7 May 2017, S.S. Zhou & X.D. Zeng M2030 (HITBC; RAF); Putao between 27.680652–27.714888N, 97.392283–97.396161E, 550–613 m, 7 November 2016, specimens pressed from cultivated plants on 24 November 2017, E. Wahlsteen EW16003 (LD [holotype of B. mariachristinae]).Published as part of Aung, Aung, Wahlsteen, Eric, Chen, Wen-Hong & Shui, Yu-Min, 2023, Begonia chenii, a synonym of B. mariachristinae (Begoniaceae) in Myanmar, pp. 97-100 in Phytotaxa 589 (1) on page 99, DOI: 10.11646/phytotaxa.589.1.10, http://zenodo.org/record/775498
Erratum: Keating et al. (2017)
No full textIn the article by Keating, X.D., Zhou, K., Liu, J., Shangguan, R., Fan, Y., and Harrison, L., “Research on Preservice Physical Education Teachers’ and Preservice Elementary Teachers’ Physical Education Identities: A Systematic Review,” in Journal of Teaching in Physical Education, 36, 2, https://doi.org/10.1123/jtpe.2016-0128, the author order was incorrectly listed. The online version of this article has been corrected.</jats:p
- …
