• Clinical and Experimental Pediatrics
• /
• v.59 no.11
• /
• pp.425-431
• /
• 2016

The waist-to-height ratio (WHtR), calculated by dividing the waist circumference (WC) by height, has recently gained attention as an anthropometric index for central adiposity. It is an easy-to-use and less age-dependent index to identify individuals with increased cardiometabolic risk. A WHtR cutoff of 0.5 can be used in different sex and ethnic groups and is generally accepted as a universal cutoff for central obesity in children (aged ${\geq}6$ years) and adults. However, the WHtR has not been validated in preschool children, and the routine use of WHtR in children under age 6 is not recommended. Prospective studies and meta-analysis in adults revealed that the WHtR is equivalent to or slightly better than WC and superior to body mass index (BMI) in predicting higher cardiometabolic risk. In children and adolescents, studies have shown that the WHtR is similar to both BMI and WC in identifying those at an increased cardiometabolic risk. Additional use of WHtR with BMI or WC may be helpful because WHtR considers both height and central obesity. WHtR may be preferred because of its simplicity and because it does not require sex- and age-dependent cutoffs; additionally, the simple message 'keep your WC to less than half your height' may be particularly useful. This review article summarizes recent publications on the usefulness of using WHtR especially when compared to BMI and WC as a screening tool for obesity and related cardiometabolic risks, and recommends the use of WHtR in clinical practice for obesity screening in children and adolescents.

• Korean Journal of Clinical Laboratory Science
• /
• v.50 no.1
• /
• pp.44-53
• /
• 2018

The WHtR (waist to height ratio) and ABSI (a body shape index) are indicators that reflect abdominal obesity. This study examined the insulin resistance and metabolic syndrome prediction ability of ABSI and WHtR. In this study, 4,395 people aged 20 years or older, who underwent physical examinations at a General Hospital in Gyeonggi-do from January 2017 to September 2017 were assessed on a cross section survey. Metabolic syndrome was defined according to the criteria of the AHA/NHLBI. Insulin resistance was judged to be insulin resistance when the HOMA-IR value was 3.0 or more. Both men and women showed a stronger correlation between WHtR and the metabolic risk factors than ABSI. The AUC value of WHtR and ABSI was 0.849 and 0.676, respectively (p<0.001). The AUC value of WHtR and ABSI for predicting insulin resistance was 0.818 and 0.641, respectively (p<0.001). In conclusion, the ABSI has low predictive power of insulin resistance and metabolic syndrome whereas the WHtR has good predictive power for metabolic syndrome and insulin resistance.

• Journal of Integrative Natural Science
• /
• v.8 no.4
• /
• pp.305-312
• /
• 2015

The present study showed WHtR to be significantly better than BMI and WC for prediction of metabolic-related diseases in the middle-aged and older people in Korea, based on Bayesian ordered probit model analysis. The variations of WC, BMI and WHtR were compared according to the number of metabolic-related diseases such as hypertension, dyslipidemia, stroke, myocardial infarction, angina pectoris and diabetes. It was found that the three measures showed the similar variation except a very few extreme cases for age less than 40. For subjects over the age of 40, WC was not significant and WHtR gave more influence in greater variability than BMI on the number of metabolic diseases. Also, the rate of change for WHtR was higher than for BMI as the number of metabolic-related diseases increased. Specifically, the difference of the marginal effect of WHtR between no disease and only one disease was 1.81 times higher than that of BMI. Moreover, it was pointed out that the threshold value of WHtR for obesity should be considered differently by age.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.16 no.11 s.102
• /
• pp.1147-1154
• /
• 2005

In this paper, we propose some PAPR(Peak to Average Power Ratio) reduction methods using WHT(Walsh Hadamard Transform) to reduce high PAPR generated in OFDM system because of multi carrier modulation. These proposed methods are the methods which has additional PAPR reduction performance without a loss of bandwidth efficiency and a large increment of calculation complexity than common PAPR reduction methods by combining the WHT with some common methods. In this paper, we propose two PAPR reduction methods made by combining a SLM(Selective Mapping) and DSI(Dummy Sequence Insertion) with a WHT. From simulation result, we can find that the PAPR reduction methods using a WHT can get about 1 dB additional PAPR reduction performance than common PAPR reduction methods; they are SLM and DSI. And, because our proposed methods have not only PAPR reduction effect, but also frequency diversity effect, more stabile data transmission is possible in nonlinear HPA and multipath fading channel.

• Exercise Science
• /
• v.28 no.1
• /
• pp.82-90
• /
• 2019

PURPOSE: The purpose of this study was to examine the association of waist to height ratio (WHtR) and resting heart rate (RHR) with cardio-metabolic risk factors among Korean postmenopausal women. METHODS: A cross-sectional analysis was performed using the 2015 Korea National Health and Nutrition Examination Survey. The analysis included a total of 1,540 postmenopausal women. RESULTS: Individuals with higher WHtR (>0.56) showed significantly higher glucose, triglyceride, insulin, Homeostatic Model Assessment for Insulin resistance (HOMA-IR), total cholesterol, systolic and diastolic blood pressure compared with ones with lower WHtR (≤0.51). Similar findings were found in those with higher RHR (≥90 bpm) compared with ones with lower RHR (<60 bpm) for glucose and HOMA-IR. When determining the combined effects of WHtR and RHR on the prevalence of metabolic syndrome, individual with WHtR above 0.5 and RHR above 80 bpm showed 10.39 times higher prevalence of metabolic syndrome compared with those with WHtR below 0.5 and RHR below 70 bpm. We further performed multiple linear regression analysis to understand how WHtR and RHR contribute to fasting glucose, and found that both WHtR and RHR contribute to fasting glucose levels independent of age, education level, marital status and income level. CONCLUSIONS: The current study showed that the WHtR and RHR are associated with cardio-metabolic risk factor and prevalence of metabolic syndrome in Korean postmenopausal women.

• The KIPS Transactions:PartC
• /
• v.12C no.4 s.100
• /
• pp.511-518
• /
• 2005

The conventional OFDM (Orthogonal Frequency Division Multiplexing) modulation can be combined with WHT (Walsh-Hadamard Transform) to reduce PAPR (Peak-to-Average Power Ratio) and improve BER (Bit Error Rate) performance. However, this WHT-based OFDM system still suffers a relatively high PAPR. Therefore, we suggest a new technique, called DGT (Data Grouping Technique) and design an OFDM system employing it and WHT to further decrease PAPR without the BER performance degradation. h salient property of DGT is the independence of the side information which is inherently a principal drawback of the well-known PAPR reduction techniques for OFDM system as well as WHT-based OFDM. The simulation programs have been also performed to verify the validity of the proposed system.

• Journal of the Korean Institute of Telematics and Electronics
• /
• v.24 no.2
• /
• pp.301-308
• /
• 1987

In this paper, we have defined the Weighted Hadamard Transform (WHT) and developed efficient algorithms for the fast computation of the WHT. The WHT is applied to digital image processing and compared with Hadamard Transform (HT). We have weighted at the center spatial frequency domains of the Hadamard Transform and transmitted a image and then center high frequencies are neglected at the receiving. The WHT of signal to noise ratio(SNR) and image quality are enhanced than the HT.

• ETRI Journal
• /
• v.43 no.2
• /
• pp.197-208
• /
• 2021

Single-carrier frequency division multiple access (SC-FDMA) is currently being used in long-term evolution uplink communications owing to its low peak-to-average power ratio (PAPR). This study proposes a new transceiver design for an SC-FDMA system based on Walsh-Hadamard transform (WHT). The proposed WHT-based SC-FDMA system has low-PAPR and better bit-error rate (BER) performance compared with the conventional SC-FDMA system. The WHT-based SC-FDMA transmitter has the same complexity as that of discrete Fourier transform (DFT)-based transmitter, while the receiver's complexity is higher than that of the DFT-based receiver. The exponential companding technique is used to reduce its PAPR without degrading its BER. Moreover, the performances of different ordered WHT systems have been studied in additive white Gaussian noise and multipath fading environments. The proposed system has been verified experimentally by considering a real-time channel with the help of wireless open-access research platform hardware. The supremacy of the proposed transceiver is demonstrated based on simulated and experimental results.

• Biomedical Science Letters
• /
• v.23 no.2
• /
• pp.57-63
• /
• 2017

A new body adiposity index (BAI) has been proposed that is expected to replace body mass index (BMI). We evaluated the correlations between metabolic syndrome risk factors and BAI, BMI, and other adiposity indices, such as waist circumference (WC), waist-to-hip ratio (WHR), and waist-to-height ratio (WHtR), by sex in the Korean population. We also evaluated whether BAI would be useful to diagnose metabolic syndrome. A total of 20,961 Korean adults who underwent health examinations were included in this study. The metabolic syndrome diagnostic criteria used in this study were those set by the American Heart Association/National Heart, Lung, and Blood Institute (AHA/NHLBI). In men (12,719), BMI and WHtR were more strongly correlated to metabolic syndrome risk than BAI, and in women (8,242), WHtR showed the strongest association with metabolic syndrome risk. BAI (area under the curve [AUC] = 0.678) presented lower discriminatory capacity than that of BMI (AUC = 0.836) for diagnosing metabolic syndrome. Moreover, BAI underestimated fat levels in men and women when considering the ability to discriminate overweight and obese individuals. In conclusion, WHtR and BMI in men, and WHtR in women may be better candidates than BAI to evaluate metabolic risk factors in Korean adults.

• Journal of the Institute of Electronics Engineers of Korea TC
• /
• v.44 no.1
• /
• pp.132-137
• /
• 2007

Jacket transforms are a class of transforms which are simple to calculate, easily inverted and are size-flexible. Previously reported jacket transforms were generalizations of the well-known Walsh-Hadamard transform (WHT) and the center-weighted Hadamard transform (CWHT). In this paper we present a new class of jacket transform not derived from either the WHT or the CWHT. This class of transform can be applied to any even length vector, and is applicable to finite fields and is useful for constructing error control codes.