http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Hyein Lee,Seungwhun Paik,Youngsoo Shin IEEE 2010 IEEE transactions on computer-aided design of inte Vol.29 No.3
<P>Pulsed latches, latches driven by a brief clock pulse, offer the same convenience of timing verification and optimization as flip-flop-based circuits, while retaining the advantages of latches over flip-flops. But a pulsed latch that uses a single pulse width has a lower bound on its clock period, limiting its capacity to deal with higher frequencies or operate at lower <I>Vdd</I>. The limitation still exists even when clock skew scheduling is employed, since the amount of skew that can be assigned and realized is practically limited due to process variation. For the first time, we formulate the problem of allocating pulse widths, out of a small discrete number of predefined widths, and scheduling clock skews, within a predefined upper bound on skew, for optimizing pulsed latch-based sequential circuits. We then present an algorithm called <I>PWCS_Optimize</I> (pulse width allocation and clock skew scheduling, PWCS) to solve the problem. The allocated skews are realized through synthesis of local clock trees between pulse generators and latches, and a global clock tree between a clock source and pulse generators. Experiments with 65-nm technology demonstrate that combining a small number of different pulse widths with clock skews of up to 10% of the clock period yield the minimum achievable clock period for many benchmark circuits. The results have an average figure of merit of 0.86, where 1.0 indicates a minimum clock period, and the average reduction in area by 11%. The design flow including <I>PWCS_Optimize</I>, placement and routing, and synthesis of local and global clock trees is presented and assessed with example circuits.</P>
Lee Hyein,박선우,CUI MEIYAN,Lee Byungkwan,Minh Pham Duy,Hwang Hyunseung,전창후 한국원예학회 2023 Horticulture, Environment, and Biotechnology Vol.64 No.2
The lighting source is one of the most critical environmental elements in a plant factory for plant production. In this study, the narrow spectrum of blue LEDs (B) was added to mint-white LEDs (MW), resulting in diff erent spectral distributions of white lights. Strawberry propagules and runner plants were grown for 21 days under 100% MW, 80% MW and 20% B, 50% of each MW and B, or 100% B to identify the eff ects of additional blue to white LEDs on their growth. Additionally, the propagation periods for three runner plants were recorded to achieve greater effi ciency with these lighting treatments. As a result, propagules and runner plants showed the greatest growth and development in the 80% MW and 20% B. The same lighting treatment had the shortest propagation cycles in the 1st, 2nd, and 3rd runner plants, 13.2, 24.9, and 35.2 days, respectively, indicating that growth promotion reduces the propagation cycle. However, 100% B caused runner growth retardation on strawberry plant and this resulted the prolongation of propagation cycle. There was no signifi cant diff erence in net photosynthetic rate for propagules, however, the runner plant was signifi cantly lowest in 100% MW. The intercellular CO2 concentration and stomatal conductance to CO 2 transfer of runner plants showed signifi cant diff erences similar to net photosynthetic rate. These experimental results suggest that the optimal amount of blue light could promote strawberry plant growth and strawberry runner plants’ growth.
Electron transport mechanism of bathocuproine exciton blocking layer in organic photovoltaics
Lee, Jeihyun,Park, Soohyung,Lee, Younjoo,Kim, Hyein,Shin, Dongguen,Jeong, Junkyeong,Jeong, Kwangho,Cho, Sang Wan,Lee, Hyunbok,Yi, Yeonjin The Royal Society of Chemistry 2016 Physical chemistry chemical physics Vol.18 No.7
<P>Efficient exciton management is a key issue to improve the power conversion efficiency of organic photovoltaics (OPVs). It is well known that the insertion of an exciton blocking layer (ExBL) having a large band gap promotes the efficient dissociation of photogenerated excitons at the donor-acceptor interface. However, the large band gap induces an energy barrier which disrupts the charge transport. Therefore, building an adequate strategy based on the knowledge of the true charge transport mechanism is necessary. In this study, the true electron transport mechanism of a bathocuproine (BCP) ExBL in OPVs is comprehensively investigated by in situ ultraviolet photoemission spectroscopy, inverse photoemission spectroscopy, density functional theory calculation, and impedance spectroscopy. The chemical interaction between deposited Al and BCP induces new states within the band gap of BCP, so that electrons can transport through these new energy levels. Localized trap states are also formed upon the Al-BCP interaction. The activation energy of these traps is estimated with temperature-dependent conductance measurements to be 0.20 eV. The Al-BCP interaction induces both transport and trap levels in the energy gap of BCP and their interplay results in the electron transport observed.</P>
Development of a compact optical torque sensor with decoupling axial-interference effects for pHRI
Lee, Hyein,Kim, Sangjoon J.,Chang, Handdeut,Kim, Jung Elsevier 2018 Mechatronics Vol.52 No.-
<P>This paper presents the design of an optical torque sensor that can structurally decouple the effect of axial-interference for use in various robotics applications. Torque sensors are widely used in the joints of intelligent service or wearable robots to realize safe human-robot interaction. Whole robot body sensing using torque sensors is essential for safe interaction. However, most torque sensors are bulky, heavy and expensive. Therefore, many optical-based torque sensors have been proposed to deal with such problems, but the issue of axial-interference still remains. We resolved the axial-interference problem via the geometrical structure of the sensor body and differential signaling using two reflective optical sensors. The moment interference error was successfully decreased from 4.49% (with one optical sensor) to 0.11% (with two optical sensors) using the proposed sensor structure while maintaining a compact size, lightweight, and low cost. Static tests and dynamic tests were carried out and analyzed for accuracy error, hysteresis, and repeatability. We then compared the performance of an impedance controller that is widely used in service and wearable robots using the proposed sensor and a commercial torque sensor with respect to various control loop rates. The control performance of the proposed sensor was comparable to that of commercial sensors.</P>