• 제어로봇시스템학회논문지
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• 제22권8호
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• pp.665-670
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• 2016

This paper proposes a repeat-back jamming signal detection scheme using a correlation ratio test metric of a combined pseudo-random noise signal for global navigation satellite systems. The correlation ratio test metric allows for the monitoring of possible distortions in the signal correlation. The proposed scheme is a modified version of the correlation ratio test metric to detect a repeat-back jamming signal in a multipath environment. Through a Monte-Carlo simulation, it is confirmed that the proposed scheme detects almost the whole case, which is received a repeat-back jamming signal under the 6 dB jamming to signal power ratio.

• 산업경영시스템학회지
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• 제36권1호
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• pp.96-102
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• 2013

This paper makes a detailed comparison between two metrics designed for measuring customer's satisfaction in the retail industry. The first metric, which is called the customer service level, has not been widely used due to the intrinsic requirement on the parameter assumption(s) of the demand distribution. Unlike the customer service level metric the in stock ratio metric does not require any requirements on the demand distribution. And the in stock ratio metric is also very easy to understand the meaning. To develop the detailed planning activities for business with the in stock ratio metric on hand one should collect some information as following : 1) POS (Point of sales) data, 2) Inventory Data 3) Inventory Trend.

• 품질경영학회지
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• 제31권4호
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• pp.239-246
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• 2003

Dynamic robust design has been regarded as the most powerful design methodology for improving product quality, Dynamic SN ratio adopted in dynamic robust design combines two major quality attributes, the variability around the linear function and the slope of the linear function, into a single design metric. The principal shortcoming associated with the dynamic SN ratio is that the metric is independent of designer's preferences for the quality attributes due to priori sets of attribute tradeoff values inherent in it. Therefore, a more rigorous preference­based design metric to accurately capture designer's intent and preference is needed. A new design metric that can be used in dynamic robust design is proposed. The effectiveness of the proposed design metric is examined with the aid of a demonstrative case study and the results are discussed.

• Kyungpook Mathematical Journal
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• 제47권4호
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• pp.595-600
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• 2007

In this paper we consider weighted arithmetic and geometric means of several positive definite operators proposed by Sagae and Tanabe and we establish a reverse inequality of the arithmetic and geometric means via Specht ratio and the Thompson metric on the convex cone of positive definite operators.

• 한국통신학회논문지
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• 제33권6C호
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• pp.487-497
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• 2008

본 논문에서는 MIMO(Multiple-input Multiple-output) 시스템에서 실시간으로 변하고 있는 채널의 상태를 추정하여 각 layer에서 survivor path들의 개수인, M을 효율적으로 조절하는 적응형 QRD-M 기법을 제안한다. 채널 상태와 상관없이 고정된 M을 사용하는 기존의 QRD-M 기법은 MLD(maximum-likelihood detection)의 성능에 근접하기 위해 correct path를 놓치지 않기 위한 큰 값의 M을 사용하여야 하므로, 큰 계산양이 요구된다. 이를 보완하기 위해 채널 행렬의 성분을 이용하여 채널 상태를 추정하여, M을 적절히 조절하는 기법이 제안되었으나 매 프레임에서 변하고 있는 채널 이득 성분만을 이용할 뿐 매 순간 바뀌고 있는 수신 잡음에 대한 정보를 이용하지 못하는 단점을 가진다. 본 논문에서는 잡음 전력 값을 측정하지 않고서도 채널 이득뿐 아니라 순간적인 수신 잡음에 대한 정보 가지 모두 반영한 채널 indicator를 이용하여 M을 더욱더 효율적으로 조절하는 QRD-M 기법을 제안한다. 채널환경이 좋은 경우에는 그렇지 못한 경우에 비해, 가장 작은 path metric 값이 다른 path의 metric 값들에 비해 확연히 작다는 사실을 이용하여, 가장 작은 값을 가지는 두 path medic의 비(ratio)를 채널상태를 추정하는 indicator로 이용하였다. 제안된 기법은 M을 적절하게 조절하므로 MLD에 근접하는 최적의 성능을 가지면서, 기존의 QRD-M 기법에 비해 계산양은 확연히 감소 시킨다.

• Journal of Communications and Networks
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• 제18권3호
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• pp.327-332
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• 2016

The routing protocol for low-power and lossy networks (RPL) is an internet protocol based routing protocol developed and standardized by IETF in 2012 to support a wide range of applications for low-power and lossy-networks (LLNs). In LLNs consisting of resource-constrained devices, the energy consumption of battery powered sensing devices during network operations can greatly impact network lifetime. In the case of inefficient route selection, the energy depletion from even a few nodes in the network can damage network integrity and reliability by creating holes in the network. In this paper, a composite energy-aware node metric ($RER_{BDI}$) is proposed for RPL; this metric uses both the residual energy ratio (RER) of the nodes and their battery discharge index. This composite metric helps avoid overburdening power depleted network nodes during packet routing from the source towards the destination oriented directed acyclic graph root node. Additionally, an objective function is defined for RPL, which combines the node metric $RER_{BDI}$ and the expected transmission count (ETX) link quality metric; this helps to improve the overall network packet delivery ratio. The COOJA simulator is used to evaluate the performance of the proposed scheme. The simulations show encouraging results for the proposed scheme in terms of network lifetime, packet delivery ratio and energy consumption, when compared to the most popular schemes for RPL like ETX, hop-count and RER.

• ETRI Journal
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• 제46권1호
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• pp.106-117
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• 2024

Large language models (LLMs) have revolutionized various applications in natural language processing and exhibited proficiency in generating programming code. We propose a framework for evaluating the code generation ability of LLMs and introduce a new metric, pass-ratio@n, which captures the granularity of accuracy according to the pass rate of test cases. The framework is intended to be fully automatic to handle the repetitive work involved in generating prompts, conducting inferences, and executing the generated codes. A preliminary evaluation focusing on the prompt detail, problem publication date, and difficulty level demonstrates the successful integration of our framework with the LeetCode coding platform and highlights the applicability of the pass-ratio@n metric.

• 한국통신학회논문지
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• 제34권11A호
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• pp.862-869
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• 2009

본 논문에서는 순간적인 채널 상태에 따라 K, 즉 survivor path의 개수를 적응적으로 조절하는 MIMO(Multiple Input Multiple Output) 검출 기법을 제안한다. 최적의 성능을 가지지만 높은 복잡도의 단점을 가지는 MLD(Maximum Likelihood Detection)의 단점을 개선하기 위해 MLD에 근접한 성능을 가지면서 복잡도는 확연히 감소시킨, 적응형 K-best SD (Sphere Decoding) 기법들이 제안되었지만, 채널 상태를 판별하기 위한 지표로, 채널의 페이딩 이득만을 이용할 뿐 순시적인 SNR(Signa1 to Noise Ratio) 값은 반영하지 못하는 단점을 가진다. 제안된 기법은 이러한 단점을 보완하기 위해 K를 조절하기 위한 채널 지표로 채널의 페이딩 성분뿐 아니라 SNR 성분까지 반영하는 path metric 값의 특성을 이용하여, 기존의 기법과 동일한 성능을 가지면서 낮은 복잡도를 가진다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제7권12호
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• pp.3037-3054
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• 2013

Interference between primary user (PU) and secondary user (SU) transceivers should be mitigated in order to implement underlay spectrum sharing in cognitive radio networks (CRN). Considering this scenario, an improved joint subcarrier and bit allocation scheme for cognitive user with primary users' cooperation (PU Coop) in CRN is proposed. In this scheme, the optimization problem is formulated to minimize the average interference power level at the PU receiver via PU Coop, which guarantees a higher primary signal to interference plus noise ratio (SINR) while maintaining the secondary user total rate constraint. The joint optimal scheme is separated into subcarrier allocation and bit assignment in each subcarrier via arith-metric geo-metric (AM-GM) inequality with asymptotical optimization solution. Moreover, the joint subcarrier and bit optimization scheme, which is evaluated by the available SU subcarriers and the allocated bits, is analyzed in the proposed PU Coop model. The performance of cognitive spectral efficiency and the average interference power level are investigated. Numerical analysis indicates that the SU's spectral efficiency increases significantly compared with the PU non-cooperation scenario. Moreover, the interference power level decreases dramatically for the proposed scheme compared with the traditional Hughes-Hartogs bit allocation scheme.

• 한국기계가공학회지
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• 제7권1호
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• pp.22-31
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• 2008

The operating window method is a novel approach in quality improvement. But it has not received deserved attention in academic research. If a critical factor for competing failure modes can be identified, the probability of failure can be reduced by widening the operating window of this factor. Traditional SN ratio for the operating window advocated by Taguchi has a critical shortcoming, which has been derived under the assumption that failure rates are determined by the operating window factor only. A new metric for robustness is given for the operating window method, which has relaxed the restrictive assumption of Taguchi's SN ratio. And procedures for determining optimal conditions based on the new metric is presented. The effectiveness of the proposed approach over the traditional practice is tested with the aid of a wave soldering process.