• JSTS:Journal of Semiconductor Technology and Science
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• v.10 no.2
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• pp.118-129
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• 2010

A lower-threshold-voltage (LVth) SRAM cell with an elevated cell biasing scheme, which enables to reduce the random threshold-voltage (Vth) variation and to alleviate the stability-degradation caused by word-line (WL) and cell power line (VDDM) disturbed accesses in row and column directions, has been proposed. The random Vth variation (${\sigma}Vth$) is suppressed by the proposed LVth cell. As a result, the LVth cell reduces the variation of static noise margin (SNM) for the data retention, which enables to maintain a higher SNM over a larger memory size, compared with a conventionally being used higher Vth (HVth) cell. An elevated cell biasing scheme cancels the substantial trade-off relationship between SNM and the write margin (WRTM) in an SRAM cell. Obtained simulation results with a 45-nm CMOS technology model demonstrate that the proposed techniques allow sufficient stability margins to be maintained up to $6{\sigma}$ level with a 0.5-V data retention voltage and a 0.7-V logic bias voltage.

• Toxicological Research
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• v.18 no.1
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• pp.99-106
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• 2002

The United States Environmental Protection Agency (EPA) characterized the cancer hazard of di(2-ethylhexyl)-phthalate (DEHP) as a B2 group (probable human carcinogen) and proposed "Guide-lines for Carcinogen Risk Assessment". This guidelines proposed alternative methods for analyzing carcinogen dose-response data and for extrapolating the effects of observed at high dose to predict that might occur at lower doses relevant to human exposure. This proposed guidelines state that "If in a particular case, the evidence indicated a threshold, as in the case of carcinogenicity being secondary to another toxicity that has a threshold, the margin of exposure analysis for toxicity is the same as is done for a non-cancer endpoint". DEHP is excellent candidate for reconideration under the new guidelines for carcinogen risk assessment (John Doull et al., 1998). This study is conducted about risk assessment for infant exposure on DEHP in powdered milk wing methodology in EPA's new guideline on carcinogenic risk assessment. Estimated cancer risk of DEHP in powdered milk and cow milk is 2.83$\times$$10^5$ (using cancer potency: 1.4$\times$$10^2$/ (mg/kg/day)) as mean and MOE is 12075 (using selected NOEL 20 mg/kg/day) as mean. mg/kg/day) as mean.

• Transactions on Electrical and Electronic Materials
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• v.7 no.1
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• pp.1-6
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• 2006

Hot carrier degradation and roll off characteristics of threshold voltage ($V_{t1}$) on NMOSFETs as I/O transistor are studied as a function of Lightly Doped Drain (LDD) structures. Pocket dose and the combination of Phosphorus (P) and Arsenic (As) dose are applied to control $V_{t1}$ roll off down to the $10\%$ gate length margin. It was seen that the relationship between $V_{t1}$ roll off characteristic and substrate current depends on P dopant dose. For the first time, we found that the n-p-n transistor triggering voltage ($V_{t1}$) depends on drain current, and both $I_{t2}$ and snapback holding voltage ($V_{sp}$) depend on the substrate current by characterization with a transmission line pulse generator. Also it was found that the improved lifetime for hot carrier stress could be obtained by controlling the P dose as loosing the $V_{t1}$ roll off margin. This study suggests that the trade-off characteristic between gate length margin and channel hot carrier (CHC) lifetime in NMOSFETs should be determined by considering Electrostatic Discharge (ESD) characteristic.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.53 no.10
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• pp.510-514
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• 2004

In this paper, we analytically examine the voltage transfer function dependent on input conditions for an N-Input NAND Gate. The logic threshold voltage, defined as a voltage at which the input and the output voltage become equal, changes as the input condition changes for a static NAND Gate. The logic threshold voltage has the highest value when all the N-inputs undergo transitions and it has the lowest value when only the last input connected to the last NMOS to ground, makes a transition. This logic threshold voltage difference increases as the number of inputs increases. Therefore, in order to provide a near symmetric voltage transfer function, a multistage N-Input Gate consisting of 2-Input Logic Gates is desirable over a conventional N-Input Gate.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.7 no.11
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• pp.2597-2615
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• 2013

This paper proposes a dynamic downlink load control scheme that jointly employs dynamic load threshold management and virtual coverage management schemes to reduce the degree of performance degradation due to traffic overload in two-tier femtocell networks. With the proposed scheme, the downlink load in a serving macrocell is controlled with a load threshold which is adjusted dynamically depending on the varying downlink load conditions of neighboring macrocells. In addition, traffic overloading is alleviated by virtually adjusting the coverage of the overloaded serving macrocell, based on the adjusted load threshold of the serving macrocell. Simulation results show that the proposed scheme improves the performance of two-tier femtocell networks in terms of the outage probability and sum throughput. This improvement is significantly increased with appropriate values of load thresholds and with an intermediate-level adjustment of the virtual coverage area (i.e., handover hysteresis margin: HOM). Furthermore, the proposed scheme outperforms both a previously proposed load control scheme with a static load threshold and the LTE system without a HOM adjustment.

• The korean journal of orthodontics
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• v.44 no.6
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• pp.294-303
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• 2014

Objective: The purpose of this study was to examine whether orthodontic treatment experience affects the individual's perception of smile esthetics and to evaluate differences among orthodontically treated laypersons, non-treated laypersons, and dentists by using computerized image alterations. Methods: A photograph of a woman's smile was digitally altered using a software image editing program. The alterations involved gingival margin height, crown width and length, incisal plane canting, and dental midline of the maxillary anterior teeth. Three groups of raters (orthodontically treated laypersons, non-treated laypersons, and dentists) evaluated the original and altered images using a visual analog scale. Results: The threshold for detecting changes in maxillary central incisor gingival margin height among laypersons was 1.5 mm; the threshold of dentists, who were more perceptive, was 1.0 mm. For maxillary lateral incisor crown width and height, the threshold of all three groups was 3.0 mm. Canting of the incisal plane was perceived when the canting was 3.0 mm among non-treated laypersons, 2.0 mm among treated laypersons, and 1.0 mm among dentists. Non-treated laypersons could not perceive dental midline shifts; however, treated laypersons and dentists perceived them when the shift was ${\geq}3.0mm$. Conclusions: Laypersons with and without orthodontic treatment experience and dentists have different perceptions of smile esthetics. Orthodontically treated laypersons were more critical than non-treated laypersons regarding incisal plane canting and dental midline shifts. Based on these findings, it is suggested that orthodontic treatment experience improved the esthetic perceptions of laypersons.

• JSTS:Journal of Semiconductor Technology and Science
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• v.3 no.2
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• pp.83-88
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• 2003

The reset operation of a CCD image sensor was improved using charge trapping of a MOS structure to realize a loe voltage driving. A DC bias generating circuit was added to the reset structure which sets reference voltage and holds the signal charge to be detected. The generated DC bias is added to the reset pulse to give an optimized voltage margin to the reset operation, and is controlled by adjustment of the threshold voltage of a MOS transistor in the circuit. By the pulse-type stress voltage applied to the gate, the electrons and holes were injected to the gate dielectrics, and the threshold voltage could be adjusted ranging from 0.2V to 5.5V, which is suitable for controlling the incomplete reset operation due to the process variation. The charges trapped in the silicon nitride lead to the positive and negative shift of the threshold voltage, and this phenomenon is explained by Poole-Frenkel conduction and Fowler-Nordheim conduction. A CCD image sensor with $492(H){\;}{\times}{\;}510(V)$ pixels adopting this structure showed complete reset operation with the driving voltage of 3.0V. The resolution chart taken with the image sensor shows no image flow to the illumination of 30 lux, even in the driving voltage of 3.0V.

• Analyses & Alternatives
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• v.3 no.1
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• pp.63-92
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• 2019

What motivates split-ticket voting in mixed electoral systems, where voters choose one party in district races and another party on the party list ballot? While much of the literature assumes strategic intent, three aspects commonly are overlooked: the competitiveness of district races, the presence of a district candidate from one's preferred party, and whether voters know the electoral threshold for party list seats. Furthermore, few studies disaggregate types of split-ticket voting (e.g. not voting for one's preferred party in a district vs. party list). Taiwan provides an intriguing case study for analysis, not only as a relatively new adopter of a mixed system, but also the presence of additional conditions that would encourage at least the consideration of a split ticket. Using survey data from the Taiwan's Election and Democratization Studies (TEDS) after the Taiwan's 2016 Legislative Yuan election, this analysis finds that knowing the threshold, the winner's margin, and the placement of a district candidate from one's preferred party all influence split-ticket voting among those with a partisan preference. However, closer inspection identifies a distinction between defecting from the district versus the party list. Evidence shows that district competitiveness and candidate placement influences defection from the district candidate, while the electoral threshold influences defection from the party list. The results add to our understanding of strategic and non-strategic incentives in mixed systems.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.22 no.12
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• pp.1165-1171
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• 2011

In this paper, we investigate hidden node problem to effectively utilize TV band devices(TVBDs) in the TV white space(TVWS), and also to protect digital television(DTV) service in Korea. Firstly, we classify the radio propagation environment into an urban area, a basin area, and a coastal area based on geographical characteristics. Thereafter, we measure and analyze local shape based hidden node attenuation at eight segmented positions in each geographic area. Because commercial buildings as well as residential and commercial buildings in Korea are located in closer proximity to each other than in other countries, hidden node margin should be more than 38 dB in order to safely protect DTV service in Korea.

• Transactions of the Korean Society of Automotive Engineers
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• v.8 no.6
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• pp.259-266
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• 2000

Crash test data from different impact modes and threshold speeds were used to assess the effects of impact conditions on air bag electronic single point sensing (ESPS) activation requirements. The requirements are expressed in terms of the desired sensor activation time based on unbelted driver dummy kinematics. A crash discriminator pre-displacement is introduced to crash recognition algorithm to the ESPS. The new crash recognition algorithm named Velocity Energy Pre-displacement(VEPD) method is developed and the ESPS algorithm based on the VEPD technique is used to assess the ESPS system performance. It is shown that VEPD method correlates very well with desired sensor activation time and meets the activation requirement.