• Journal of Mechanical Science and Technology
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• v.18 no.2
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• pp.286-293
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• 2004

The air fuel ratios of current gasoline engines are almost controlled by several air flow meters. When CVVT (Continuous Variable Valve Timing) is applied to a gasoline engine for higher engine performance, the MAP (Manifold Absolute Pressure) sensor is difficult to follow the instantaneous air fuel ratio due to the valve timing effect. Therefore, a HFM (Hot Film Flow Meter) is widely used for measuring intake air flow in this case. However, the HFMs are incapable of indicating to reverse flow, the oscillation of intake air flow has an negative effect on the precision of the HFM. Consequently, the various duct configurations in front of the air flow sensor affect the precision of HFM sensitivity. This paper mainly focused on the analysis of the reverse flow, flow fluctuation in throttle upstream and the geometry of intake system which influence the HFM measurement.

• The Journal of the Acoustical Society of Korea
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• v.42 no.1
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• pp.25-31
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• 2023

In order to estimate the radial speed of an underwater object so-called target with active sonar, Continuous Wave (CW) pulse is generally used, but if a target is slow and at near distance, it is not easy to estimate the radial velocity of the target due to acoustic reverberation in the ocean. In 2017, Wang et al. utilized broadband signal of two Hyperbolic Frequency Modulation (HFM) pulses, which is known as a doppler-invariant pulse, with equal frequency band and in opposite sweep directions to overcome this problem and successfully estimate the radial speed of slow-moving nearby target. They demonstrated the estimation of the radial velocity with computer simulation using the parameters of two HFM starting time differences and receiving times. However, for it uses two HFM pulses with equal frequency, cross-correlation between the two pulses negatively affect the detection performance. To mitigate this cross-correlation effect, we suggest using two different band HFM with the opposite sweep directions. In this paper, a method of radial velocity estimation is derived and simulated using two HFM pulses with the pulse length of 1 second and bandwidth of 400 Hz. Applying the suggested method, the radial velocity was estimated with approximately 6 % of relative error in the simulation.

• Fisheries and Aquatic Sciences
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• v.24 no.3
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• pp.109-120
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• 2021

Protein hydrolysates and krill meal (KM) are used as protein sources in aquafeeds. The study was conducted to examine the supplemental effects of shrimp protein hydrolysates (SH) or KM in a high-plant-protein diet for red seabream (Pagrus major). A fish meal (FM)-based diet (40%) was considered as the high-FM diet (HFM) and a diet containing 25% FM and soy protein concentrate, in the expense of FM protein from HFM diet, was considered as the low fish meal (LFM) diet. Two other experimental diets (SH and KM) were prepared by including SH and KM into LFM diet at 5% inclusion levels in exchange of 5% FM from the LFM diet. A feeding trial was conducted for fifteen weeks using triplicate group of fish (Initial mean body weight, 8.47 ± 0.05 g) for a diet. Growth performance and feed efficiency of fish were significantly enhanced by HFM, KM and SH supplemented diets over those of fish fed LFM diet. Interestingly, these parameters of fish fed SH diet showed better performance than KM and HFM groups. Liver IGF-I expression of fish fed SH diet was comparable to HFM group and higher than KM and LFM diets. Protein digestibility of SH diet was significantly higher than KM, HFM, and LFM diets. Dry matter digestibility of SH diet was comparable to HFM diet and significantly higher than KM and LFM diets. Nitro blue tetrazolium and superoxide dismutase activities of HFM, SH and KM groups were significantly elevated than the LFM group and SH diet increased catalase and glutathione peroxidase activities of fish compared to KM and LFM groups. Hemoglobin level and hematocrit of fish fed SH and KM diets were significantly higher than LFM group. A diet containing 20% FM with KM is comparable to a HFM diet which contains 40% FM for red seabream. SH can be used to replace FM from red seabream diet down to 20% and fish performance can be improved better than a diet containing 40% FM. Overall, it seems that SH is more effective ingredient in red seabream diet compared to KM.

• The Journal of the Acoustical Society of Korea
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• v.21 no.4
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• pp.387-393
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• 2002

The enhancement technique of noise signal using mixture HFM (Midden Filter Model) are proposed. Given the parameters of the clean signal and noise, noisy signal is modeled by a linear state-space model with Markov switching parameters. Estimation of state vector is required for estimating original signal. The estimation procedure is based on mixture interacting multiple model (MIMM) and the estimator of speech is given by the weighted sum of parallel Kalman filters operating interactively. Simulation results showed that the proposed method offers performance gains relative to the previous results with slightly increased complexity.

• Journal of Environmental Health Sciences
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• v.27 no.3
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• pp.107-112
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• 2001

This work reports the application of a hollow fiber module(HFM) for Cr(VI) extraction from heavy metal salts mixed solution by using microporous hydrophobic hollow fiber module. In HFM configuration, the organic extraction used for the extraction of Cr(VI) was di-(2-ethyl hexyl) phosphoric acid(D2EHPA) diluted with n-heptane. The study of HFM includes the influence of hydrodynamic and chemical condition, i.e., the flow rate of feed solution, the time of reactive extraction, the concentration of feed solution, and the pH of aqueous phase solutions. Several experiments with synthetic solution of different mixed components system of Cr(VI) solutions established optimum condition to achieve a clean separation of Cr(VI). It was possible to separate Cr(VI) in the presence of metal salts mixed solution, such as Zn(II), Ni(II), Cu(II), and Cd(II) using the HFM technique.

• Journal of the Institute of Electronics and Information Engineers
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• v.51 no.8
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• pp.11-19
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• 2014

In recent SONAR (sound navigation and ranging) systems, wideband active SONAR systems has received more attention than narrowband SONAR systems due to the remarkable detection performance in terms of range resolution. However, the wideband SONAR systems usually requires a huge amount of computational burden in order to achieve their own superiority. To cope with this drawback of the wideband SONAR systems, this paper proposes a fast target detection and velocity estimation method using an extended replica in wideband hyperbolic frequency modulation active SONAR system. Computer simulation shows that the proposed method can be implemented by a highly reduced computational complexity with a little performance degradation in target detection and velocity estimation compared to the conventional filter bank method.

• Nutrition Research and Practice
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• v.3 no.1
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• pp.31-37
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• 2009

Recently, Korean people are consuming seaweeds almost 3.5 times more now than three decades ago. It is well known that seaweeds contain lots of soluble dietary fiber in addition to micronutrients such as ${\beta}$-carotene, iodine and some bioactive components. Seaweeds are considered to be effective for preventing chronic diseases including obesity, diabetes mellitus, atherosclerosis, cancer or constipation. This study was conducted to investigate the effect of seamustard intake on body weight gain, blood glucose level and lipid profiles in rats fed diets with different energy nutrient composition. Male Sprague-Dawley rats (average initial weight 103.7g) were divided into groups for two experiments as follows; Control, M2.5 & M5 groups (Exp. I) and M5, M10, HCM5, HCM10, HFM5 & HFM10 groups (Exp. II). The rats were fed diet and water ad libitum for 4 weeks. In general, there was no significant difference in blood glucose and triglyceride concentration among groups. In Exp. I, serum LDL-cholesterol level of rats fed diet with 5% seamustard powder (M5) was significantly lower than that of control group, while HDL-cholesterol level, TC/LDL ratio and weight of adrenal gland were higher. In Exp. II, food intake, body weight gain and EER of high fat diet with 10% seamustard group (HFM10) were the lowest among groups. Except gastrocnemius muscle, all organ weights of HFM10 group were the lowest. Fecal cholesterol excretion and serum LDL-cholesterol concentration of HFM10 group were the highest, while serum HDL-cholesterol level was the lowest among groups. Interestingly, HDL-cholesterol concentration was the highest in HCM5 group among groups. From these results, it was suggested that seamustard intake might be more effective for body weight control, but not for improving blood lipid profiles in high fat diet than in high carbohydrate diet.

• The korean journal of orthodontics
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• v.30 no.1 s.78
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• pp.43-52
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• 2000

Hemifacial microsomia ( HFM ) is the second most common craniofacial abnormalies. HFM represnted a spectrum of clinical findings such as hypoplasia of the mandibular ramus and condyle, confinement of maxilla growth, external and/or middle ear defects, involvement of some cranial suture, buccal soft tissue, facial nerve, and muscles in the affected side. HFM often showed progressive facial asymmetry and occlusal plane slanting to the affected side with growth. There were several reports about asymmetry of tooth maturation, hypodontia, delayed eruption, enamel hypoplasia in HFM. Since teeth develope in close association with size and morphology of the maxillary and the mandible, it is highly likely that dental changes will be present in HFM. So the Purpose of this study was to investigate the differences of the primary and the permanent teeth dimensions in the maxillary and the mandibular dentition between the affected and the non-affected side of HFM.. The sample of this study consisted of 34 unilateral HFM Patients (18 males and 16 females, average age : 5 year 11 months old). The authors examined the mesiodistal and the faciolingual dimensions of the primary and the permanent teeth and performed statistical study by using paired t-test. The results were as follows 1. The mesiodistal dimensions of the mandibular second primary molar and the mandibular first permanent molar in the affected side of HFM were significantly smaller than those of non-affected side. But there were no significant differences in the anterior teeth and the mandibular first primary molar. It means that a gradient of severity from anterior teeth to posterior teeth was found in the mandibular dentition. 2. Although there were no significant differences in the faciolingual dimensions of the primary and the permanent teeth in the maxillary and the mandibular dentition between the affected and non-affected side of HFM, there were general trend of compensatory increase in faciolingual dimension of the mandibular primary and the permanent teeth in the affected side Therefore these results showed that HFM might affect on the abnormality of tooth dimension, especially the most posterior teeth, in the affected side of the mandible.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.32B no.11
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• pp.153-162
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• 1995

When vector quantization is used in low rate image coding (e.g., R<0.5), the primary problem is the tremendous computational complexity which is required to search the whole codebook to find the closest codevector to an input vector. Since the number of code vectors in a vector quantizer is given by an exponential function of the dimension. i.e., L=2$^{nR}$ where Rn. To alleviate this problem, a multiple shell structure of hypercube feature maps (MSSHFM) is proposed. A binary HFM of k-dimension is composed of nodes at hypercube vertices and a multiple shell architecture is constructed by surrounding the k-dimensional hfm with a (k+1)-dimensional HFM. Such a multiple shell construction of nodes inherently has a complete tree structure in it and an efficient partial search scheme can be applied with drastically reduced computational complexity, computer simulations of still image coding were conducted and the validity of the proposed method has been verified.

• Archives of Plastic Surgery
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• v.49 no.5
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• pp.642-647
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• 2022

Hemifacial microsomia (HFM) is a complex congenital condition with heterogeneous malformations of the facial skeleton that almost always involves mandibular hypoplasia. Here we introduce a unique case in which a patient with HFM had initially successful optimization of facial symmetry using a polyetheretherketone implant for mandibular augmentation. However, multiple factors associated with the intraoperative and postoperative course, including hardware failure and infection, led to diminished mechanical strength of the mandible, ultimately resulting in a mandibular fracture. In this unique case presentation of HFM, we discuss the various factors that contributed to mandibular weakness and increased susceptibility to fracture.