Inclination Of Plane Research Articles

Influence of hip replacement on sagittal alignment of the lumbar spine: An EOS study.

Changes in pelvic position can influence the sagittal alignment of the lumbar spine. The restoration of hip kinematics by hip replacement thus appears to offer the possibility of correcting sagittal alignment. This preliminary retrospective study used EOS imaging to investigate the influence of total hip arthroplasty on pelvic parameters in patients with normal preoperative pelvic parameters. Twenty patients with hip osteoarthritis undergoing total hip arthroplasty (THA) between 2011 and 2012 received unilateral THA. To evaluate the preoperative and postoperative changes of the pelvic parameters, we analyzed EOS imaging of the patients to determine pelvic incidence, sacral slope, sacral tilt, pelvic tilt, anterior pelvic plane inclination and pelvic axial rotation. Additionally, anteversion and inclination of the acetabular cup position were determined. No statistically significant difference was found between the preoperative and postoperative measurements of pelvic parameters, although the change in pelvic tilt approached significance. Postoperatively, respective average values of 42.6° and 22.7° were measured for inclination and anteversion of the acetabular cup position. THA did not influence pelvic position and sagittal alignment in patients with normal preoperative pelvic parameters. A subsequent study will investigate whether corrections of pelvic parameters outside the norm in patients with OA are possible with THA.

Comparative study of the treatment effects of bionator and bite jumping appliances on Class II malocclusions

PurposeThe purpose of this investigation was to compare and evaluate the treatment effects of two commonly used removable functional appliances. Materials and methodsThe subjects, 12 children, were all diagnosed as having maxillary protrusion. They were divided into two treatment groups: the bionator group, comprising 3 boys and 3 girls, mean age 11.3 years at the start of treatment; and the bite jumping appliance (BJA) group, comprising 5 boys and one girl, mean age 10.9 years at the start of treatment. Lateral cephalograms in the intercuspal position were taken both at the beginning and at the end of use of each appliance. ResultsIn comparison of treatment effects between both groups, the BJA group showed greater lingual inclination of the maxillary incisors and labial inclination of the mandibular incisors compared with the bionator group. Also, the BJA group showed a significantly greater forward and downward change in the inclination of the occlusal plane than did the bionator group. ConclusionsIn terms of treatment mechanics, the bionator and BJA are quite different. Therefore, the proper use of each depends on symptoms, sequence of use, and time of initiation of therapy in order to provide the most effective treatment of Class II malocclusions.

A new dimension to cephalometry: DW plane

Context: An accurate jaw relationship is critically important in orthodontic diagnosis and treatment planning. Various angular and linear measurements that have been proposed can be erroneous because they depend on various factors. Aim: The purpose of this study is to establish a new cephalometric measurement to assess the skeletal jaw discrepancy using Walker's point. Settings and Design: Lateral cephalogram of 100 Indian subjects with age range (8–11, 12–18, 19-27) were obtained. Inclusion criteria were – clinically Class I occlusion; normal overjet and overbite; orthoganthic profile; competent lips and cephalometrically normal ANB; Wits appraisal; Rakosi Jarabak's angle of inclination and mandibular plane angle. Materials and Methods: Four skeletal landmarks: Point A, Point B, Walker's point (W) and Wing point (w) were used to indicate the severity and type of skeletal dysplasia. Double W (DW) was constructed joining the Walker's and Wing point. Statistical Analysis Used: Analysis of variance test and Student's t -test was applied which showed significant results. Results: The difference between Walker's perpendicular to A Point and Walker's perpendicular to B Point gave the sagittal jaw discrepancy and was found to be 8.2 ± 0.9 mm. This measurement remained relatively constant throughout life. Conclusions: DW plane is an effective way to accurately establish the skeletal jaw relationship. It analyses the variance between linear measurements to determine the sagittal jaw relationship, linear measurements for vertical maxillary height and angular measurements to determine rotational jaw changes.

Influence of occlusal plane inclination and mandibular deviation on esthetics.

Objective: The aim of this study was to assess the degree of perception of occlusal plane inclination and mandibular deviation in facial esthetics, assessed by laypeople, dentists and orthodontists. Methods: A woman with 5.88° of inclination and 5.54 mm of mandibular deviation was selected and, based on her original photograph, four new images were created correcting the deviations and creating more symmetric faces and smiles. Examiners assessed the images by means of a questionnaire. Their opinions were compared by qualitative and quantitative analyses. Results: A total of 45 laypeople, 27 dentists and 31 orthodontists filled out the questionnaires. All groups were able to perceive the asymmetry; however, orthodontists were more sensitive, identifying asymmetries as from 4.32° of occlusal plane inclination and 4.155 mm of mandibular deviation (p< 0.05). The other categories of evaluators identified asymmetries and assigned significantly lower grades, starting from 5.88° of occlusal plane inclination and 5.54 mm of mandibular deviation (p< 0.05). Conclusion: Occlusal plane inclination and mandibular deviation were perceived by all groups, but orthodontists presented higher perception of deviations.

Experimental assessment of variant selection rules for grain boundary α in titanium alloys

In titanium alloys, variant selection (VS) of grain boundary α (GBα) at prior β grain boundaries (GBs) during α precipitation has a significant influence on the subsequent transformation pathway and transformation texture development of the α phase, and thus on the final mechanical properties. In this paper, we assess systematically the applicability of all current empirical rules for VS of GBα at prior β GBs using experimental characterization of GB misorientation, boundary plane inclination, and orientation relationships between the GBα and adjacent β grains in Ti-5553. We find that all these VS rules may be violated for a given β grain boundary. Based on the experimental observations, the frequencies of each of these empirical rules being either violated or followed have been assessed, and from this assessment, we analyze theoretically whether the arguments underlying each of these rules are physically sound and why rules are violated, and then discuss when a sound prediction may be made using these empirical VS rules.

An experimental study of the mechanical characteristics of fractured loess in western China

Microstructural changes in the loess deposits due to the presence of joint planes is one of the primary causes of the geohazards (ground fissures, ground subsidence, landslides, collapses, and soil and water losses) that occur in the loess regions of western China. By means of uniaxial tensile tests and triaxial shear tests conducted under different confining pressures, we tested fractured loess Q2 samples with five fracture plane inclination angles (0°, 30°, 45°, 60°, and 90°) taken from Sanyuan County, Shaanxi Province in western China, where geohazards are prevalent. Analysis of the tensile stress–strain and shear stress–strain relationships of the fractured loess specimens revealed the characteristics of the fractures that induce instability in this area. These results provide important baseline data for future research on the mechanism of geohazards in the loess regions of western China.

Change in acetabular version after lumbar pedicle subtraction osteotomy to correct post-operative flat back: EOS® measurements of 38 acetabula

BackgroundAbnormalities in acetabular orientation can promote the development of hip osteoarthritis, femoro-acetabular impingement, or even acetabular cup malposition. The objective of the present study was to determine whether pedicle substraction osteotomy (PSO) to correct sagittal spinal imbalance affected acetabular orientation. HypothesisPSO performed to correct sagittal spinal imbalance affects acetabular orientation by changing the pelvic parameters. Materials and methodsThis was a descriptive study in which two observers measured the acetabular parameters on both sides in 19 patients (38 acetabula) before and after PSO for post-operative flat-back syndrome. Mean time from PSO to post-operative measurements was 19months. Measurements were taken twice at a 2-week interval, on standing images obtained using the EOS® imaging system and sterEOS® software to obtain 3D reconstructions of synchronised 2D images. Acetabular anteversion and inclination were measured relative to the vertical plane. Mean pre-PSO and post-PSO values were compared using the paired t-test, and P values lower than 0.05 were considered significant. To assess inter-observer and intra-observer reproducibility, we computed the intra-class correlation coefficients (ICCs). ResultsThe measurements showed significant acetabular retroversion after PSO, of 7.6° on the right and 6.5° on the left (P<0.001). Acetabular inclination diminished significantly, by 4.5° on the right and 2.5° on the left (P<0.01). Inclination of the anterior pelvic plane decreased by 8.4° (P<0.01). Pelvic incidence was unchanged, whereas sacral slope increased by 10.5° (P<0.001) and pelvic tilt decreased by 10.9° (P<0.001). The ICC was 0.98 for both inter-observer and intra-observer reproducibility. ConclusionChanging the sagittal spinal alignment modifies both the pelvic and the acetabular parameters. PSO significantly increases sacral slope, thus inducing anterior pelvic tilt with significant acetabular retroversion. The measurements obtained using sterEOS® showed good inter-observer and intra-observer reproducibility. To our knowledge, this is the first study of changes in acetabular version after PSO.

Новый способ определения углов наклона космических снимков по известным размерам изображенных на них объектов местности

Abstract: To obtain geoinformation materials using remote sensing it is necessary to know rotation parameters of exterior orientation of the images processed. The author describes in the article a new method of satellite images angles determination, or, to be more exact, of camera focal plane inclination. Its essence is as follows: size of image pixel projection ground size is determined with photo camera focal plane inclination angle. So, if image pixel projection ground size is known, it is possible to find an inclination angle value of photo camera focal plane relatively to direction of nadir. The author’s formulas are given for determination of inclination angles (pitch and roll) of the camera focal plane according to the known values of pixel projection ground size.

Effect of kinesiotaping, non-elastic taping and bracing on segmental foot kinematics during drop landing in healthy subjects and subjects with chronic ankle instability

ObjectiveTo evaluate the effects of kinesiotape, non-elastic tape, and soft brace on segmental foot kinematics during drop landing in subjects with chronic ankle instability and healthy subjects. DesignControlled study with repeated measurements. SettingThree-dimensional motion analysis laboratory. ParticipantsTwenty participants with chronic ankle instability and 20 healthy subjects. InterventionsThe subjects performed drop landings with 17 retroreflective markers on the foot and lower leg in four conditions: barefoot, with kinesiotape, with non-elastic tape and with a soft brace. Main outcome measuresRanges of motion of foot segments using a foot measurement method. ResultsIn participants with chronic ankle instability, midfoot movement in the frontal plane (inclination of the medial arch) was reduced significantly by non-elastic taping, but kinesiotaping and bracing had no effect. In healthy subjects, both non-elastic taping and bracing reduced that movement. In both groups, non-elastic taping and bracing reduced rearfoot excursion in inversion/eversion significantly, which indicates a stabilisation effect. No such effect was found with kinesiotaping. All three methods reduced maximum plantar flexion significantly. ConclusionsNon-elastic taping stabilised the midfoot best in patients with chronic ankle instability, while kinesiotaping did not influence foot kinematics other than to stabilise the rearfoot in the sagittal plane. Clinical Trial Registration NumberClinicalTrials.gov NCT01810471.

Examination of inclinations of the spine at childhood and adolescence.

Spine is a column that consists of consecutively lined up vertebras. It includes medulla spinalis. It contributes the motions of head, neck and body. Spine is not a straight column. There is a convexity towards the front of the spine (lordosis) at cervical and lumbar areas in adults and a convexity towards the back of the spine (kyphosis) at thoracic and sacral spine areas. In this study, lateral magnetic resonance images of 731 children between 1 and 16 years of age were examined and their cervical lordosis, thoracic kyphosis and lumbar lordosis angles were measured with Cobb method using ImageJ programme for every age group. The mean calculated cervical lordosis angles in 1-16-year-old children were found to be 20.51o ± 6.11o (minimum 17.96o ± 6.29o, maximum 23.50o ± ± 4.14o). It has been observed that cervical angle values decrease with age. The mean thoracic kyphosis angle measured was 28.71o ± 6.99o (minimum 24.55o ± ± 5.65o, maximum 30.44o ± 4.68o). Lumbar lordosis angle was 28.08o ± 7.39o (minimum 20.36o ± 6.59o, maximum 32.68o ± 6.03o). Thoracic kyphosis and lumbar lordosis angle values increased with age. In our study, a statistical differ- ence was found in increasing thoracic kyphosis angle between 1-year-old group and 14-year-old group. Statistical difference was also found in decreasing cervical lordosis angle value between 1-year-old group and 16-year-old group. When we compare our study results with literature values, cervical lordosis values were similar, but lumbar lordosis values were lower. In summary, we think that knowing sagittal plane inclinations of the spine developing in childhood and adolescence will contribute to earlier de- termination of pathologies. We also hope that it will contribute to clinical stages and other studies in this field.

Motion of Grain Boundaries: Experiments on Bicrystals

Recent research on grain boundary migration is reviewed. Novel in-situ measuring techniques based on orientation contrast imaging and the experimental results obtained on specially grown bicrystals are presented. Particularly, the investigated faceting and migration behavior of low angle grain boundaries under the curvature force in aluminum bicrystals was addressed. In contrast to the pure tilt boundaries, which remained straight/flat and immobile during annealing at elevated temperatures, mixed tilt-twist boundaries readily assumed a curved shape and steadily moved under the capillary force. Computational analysis revealed that this behavior is due to the inclinational anisotropy of grain boundary energy, which in turn depends on boundary geometry. The migration of planar grain boundaries induced by a magnetic field was measured in bismuth and zinc bicrystals. Various structurally different boundaries were investigated. The results revealed that grain boundary mobility essentially depends on the misorientation angle and the inclination of the boundary plane. Stress driven boundary migration in aluminium bicrystals was observed to be coupled to a tangential translation of the grains. The activation enthalpy of high angle boundary migration was found to vary non-monotonously with misorientation angle, whereas for low angle boundaries the migration activation enthalpy was virtually the same. The motion of the mixed tilt-twist boundaries under stress was observed to be accompanied by both the translation of adjacent grains parallel to the boundary plane and their rotation around the boundary plane normal.

Dynamical masses of a nova-like variable on the edge of the period gap

We present the first dynamical determination of the binary parameters of an eclipsing SW Sextantis star in the 3–4 h orbital period range during a low state. We obtained time-resolved optical spectroscopy and photometry of HS 0220+0603 during its 2004–2005 low-brightness state, as revealed in the combined Small & Moderate Aperture Research Telescope System, IAC80 and M1 Group long-term optical light curve. The optical spectra taken during primary eclipse reveal a secondary star spectral type of M5.5 ± 0.5 as derived from molecular band-head indices. The spectra also provide the first detection of a DAB white dwarf in a cataclysmic variable. By modelling its optical spectrum we estimate a white dwarf temperature of 30 000 ± 5000 K. By combining the results of modelling the white dwarf eclipse from ULTRACAM light curves with those obtained by simultaneously fitting the emission- and absorption-line radial velocity curves and I-band ellipsoidal light curves, we measure the stellar masses to be M1 = 0.87 ± 0.09 M⊙ and M2 = 0.47 ± 0.05 M⊙ for the white dwarf and the M dwarf, respectively, and an inclination of the orbital plane of i ≈ 79°. A radius of 0.0103 ± 0.0007 R⊙ is obtained for the white dwarf. The secondary star in HS 0220+0603 is likely too cool and undersized for its mass.

No association between gingival labial recession and facial type.

To evaluate if facial type is a predictor of the development of gingival recession. A cohort of 179 orthodontic patients (76 males, 101 females; age before treatment T S = 12.4 years, SD = 0.8) were followed until 5 years post-treatment (T 5 = 20.7 years, SD = 1.2). The presence of recessions was scored ('Yes' or 'No') by two raters on initial (T S), end of treatment (T 0), and post-treatment (T 5) plaster models. A recession was noted (scored 'Yes') if the labial cemento-enamel junction was exposed. The clinical crown heights were measured at T S, T 0, and T 5 as the distances between the incisal edges and the deepest points of the curvature of the vestibulo-gingival margins. Determination of the facial type was based on the inclination of mandibular plane relative to cranial base (Sella-Nasion/Mandibular Plane) and the proportion of posterior to anterior face heights (PFHs; SGo/NMe × 100 per cent) on pre-treatment cephalograms. From T 0 to T 5, the number of subjects with recessions increased from 2 (1.1 per cent) to 24 (13.6 per cent), and the number of recession sites increased from 2 to 39. However, most patients had either one or two recession sites. The mean clinical crown height of mandibular incisors increased by 0.86mm (SD = 0.82, P < 0.001). Regression analysis showed that mandibular plane inclination had no effect on the development of gingival recession or on the increase of clinical crown heights of mandibular incisors. Facial type is not a predictor of the occurrence of gingival recession.

Structural equation modeling for alteration of occlusal plane inclination

PurposeOcclusal plane inclination is important to maintain a normal opening closing/biting function. However, there can be several causes that lead to alterations of the occlusal plane. The purpose of this study was to observe variations of occlusal plane inclination in adult patients, and to uncover the factors affecting changes in occlusal plane inclination with aging. MethodsSubjects were 143 patients. A cephalometric image was taken of these patients. In this study, our inquiry points were age, 3 variables on intra-oral findings, and 7 variables on cephalometric analysis. To evaluate the possible causes that affect occlusal plane inclination, factor analysis was carried out, and each component was treated as factors, which were then statistically applied to a structural equation model. Statistical analysis was carried out through the SPSS 20.0 (SPSS Inc., Chicago, USA). ResultsIn all patients, Camper-occlusal plane angle (COA) ranged from −25.7 to −4.9° (Mean±SD: −6.4±5.36). In the 60 patients who had no missing teeth, COA ranged from −11.6 to −4.9° (Mean±SD: −3.3±3.31).From the results of the structural analysis, it was suggested that the occlusal plane changes to counter-clockwise (on the right lateral cephalograms) with aging. ConclusionIn this study, variations of occlusal plane inclination in adult patients were observed, and the factors affecting changes in occlusal plane inclination with aging were investigated via factor analysis. From our results, it was suggested that the mandibular morphology change and loss of teeth with aging influence occlusal plane inclination.

SU‐E‐T‐244: Designing Low‐Z Targets To Enhance Surface Dose: A Monte Carlo Simulation

Purpose:Recent developments in The Varian Truebeam linac platform allows for the introduction of low‐Z targets into the beam line for the imaging purposes. We have proposed using a low‐Z target for radiation therapy purposes to enhance the surface dose during radiation treatment. The target arm of the Varian Truebeam accelerator consists of multiple targets with are linearly translated into the beam line. We have designed two Low‐Z targets made of carbon: 1) a step target consisting of three steps of 15%, 30% and 60% CSDA range for 2.5 MeV electrons Figure 1a; 2) and a ramp target, an incline plane 2cm long with thicknesses ranging from 0% to 60% CSDA range, Figure 1b. The purpose of this work will determine the spectral characteristics of these target designs and determine if they have practical clinical applications for enhancing surface dose.Methods:To calculate the spectral characteristics of these targets, a standard Monte Carlo model of a Varian Clinac accelerator was used. Simulations were performed with a carbon step target, and a carbon ramp target, located at the same position as the electron foil in the rotating carousel. Simulations were carried out using a 2.5 MeV electron beam.Results:The step target design produced spectral characteristics which were similar to spectral model using a single disk target of the same thickness. The ramp target provides a means to have positional variation of the spectral components of the beam, however, the electron component as 60% CSDA us much broader than the step target.Conclusion:The carbon step‐target provides a spectral distribution which is similar to a carbon disk of comparable thickness. The spectral distribution from the ramp‐target can be modified as a function of position to provide a wide range of low energy electrons for surface dose enhancement.

Esthetic evaluation of dental and gingival asymmetries.

The aim of this study was to determine which smile asymmetries were less esthetic, dental or gingival. Laypeople (297), generalists (223), prosthodontists (50) and orthodontists (49), evaluated the esthetics of digitally-modified images taken from the same frontal intra-oral photograph, using the same lips, simulating upper maxillary midline shift, occlusal plane inclination, asymmetric incisal edge and asymmetric gingival migration. The images were later paired into 3 groups. The only ones considered esthetic were the asymmetric incisal edge of the 0.5 mm shorter upper central incisor and the asymmetric gingival migration (2 mm) of the upper central incisor. In the paired images, upper maxillary midline shift vs. occlusal plane inclination, the former was rated less esthetic, while in the asymmetric incisal edge vs. asymmetric gingival migration pair, the latter was considered to be less esthetic. Laypeople and generalists consider smiles more attractive. The only images considered esthetic were the asymmetric incisal edge of the central incisor shorter by 0.5 mm and the 2 mm asymmetric gingival migration of the upper central incisor. In the horizontal plane (maxillary midline shift vs. occlusal plane cant), the dental asymmetries were considered less esthetic than the gingival asymmetries. However, in the vertical plane (asymmetric incisal edge vs. asymmetric gingival migration) the opposite was recorded.

STABLE CONIC-HELICAL ORBITS OF PLANETS AROUND BINARY STARS: ANALYTICAL RESULTS

Studies of planets in binary star systems are especially important because it was estimated that about half of binary stars are capable of supporting habitable terrestrial planets within stable orbital ranges. One-planet binary star systems (OBSS) have a limited analogy to objects studied in atomic/molecular physics: one-electron Rydberg quasimolecules (ORQ). Specifically, ORQ, consisting of two fully stripped ions of the nuclear charges Z and Z' plus one highly excited electron, are encountered in various plasmas containing more than one kind of ion. Classical analytical studies of ORQ resulted in the discovery of classical stable electronic orbits with the shape of a helix on the surface of a cone. In the present paper we show that despite several important distinctions between OBSS and ORQ, it is possible for OBSS to have stable planetary orbits in the shape of a helix on a conical surface, whose axis of symmetry coincides with the interstellar axis; the stability is not affected by the rotation of the stars. Further, we demonstrate that the eccentricity of the stars' orbits does not affect the stability of the helical planetary motion if the center of symmetry of the helix is relatively close to the star of the larger mass. We also show that if the center of symmetry of the conic-helical planetary orbit is relatively close to the star of the smaller mass, a sufficiently large eccentricity of stars' orbits can switch the planetary motion to the unstable mode and the planet would escape the system. We demonstrate that such planets are transitable for the overwhelming majority of inclinations of plane of the stars' orbits (i.e., the projections of the planet and the adjacent start on the plane of the sky coincide once in a while). This means that conic-helical planetary orbits at binary stars can be detected photometrically. We consider, as an example, Kepler-16 binary stars to provide illustrative numerical data on the possible parameters and the stability of the conic-helical planetary orbits, as well as on the transitability. Then for the general case, we also show that the power of the gravitational radiation due to this planet can be comparable or even exceed the power of the gravitational radiation due to the stars in the binary. This means that in the future, with a progress of gravitational wave detectors, the presence of a planet in a conic-helical orbit could be revealed by the noticeably enhanced gravitational radiation from the binary star system.

Analytical Estimation of Water-Oil Relative Permeabilities through Fractures

Modeling multiphase flow through fractures is a key issue for understanding flow mechanism and performance prediction of fractured petroleum reservoirs, geothermal reservoirs, underground aquifers and carbon-dioxide sequestration. One of the most challenging subjects in modeling of fractured petroleum reservoirs is quantifying fluids competition for flow in fracture network (relative permeability curves). Unfortunately, there is no standard technique for experimental measurement of relative permeabilities through fractures and the existing methods are very expensive, time consuming and erroneous. Although, several formulations were presented to calculate fracture relative permeability curves in the form of linear and power functions of flowing fluids saturation, it is still unclear what form of relative permeability curves must be used for proper modeling of flow through fractures and consequently accurate reservoir simulation. Basically, the classic linear relative permeability (X-type) curves are used in almost all of reservoir simulators. In this work, basic fluid flow equations are combined to develop a new simple analytical model for water-oil two phase flow in a single fracture. The model gives rise to simple analytic formulations for fracture relative permeabilities. The model explicitly proves that water-oil relative permeabilities in fracture network are functions of fluids saturation, viscosity ratio, fluids density, inclination of fracture plane from horizon, pressure gradient along fracture and rock matrix wettability, however they were considered to be only functions of saturations in the classic X-type and power (Corey [35] and Honarpour et al. [28, 29]) models. Eventually, validity of the proposed formulations is checked against literature experimental data. The proposed fracture relative permeability functions have several advantages over the existing ones. Firstly, they are explicit functions of the parameters which are known for each of simulation computational cells or easy to measure in laboratory. It is also the first model that takes gravity effects and wettability of fracture walls into consideration and individually developed for water and oil-wet systems. Furthermore, the newly developed formulations are simple, efficient and accurate. Thus, they are recommended for implementation in dual and multiple continuum commercial reservoir simulators.

Using the inclinations of Kepler systems to prioritize new Titius–Bode-based exoplanet predictions

We analyze a sample of multiple-exoplanet systems which contain at least 3 transiting planets detected by the Kepler mission ("Kepler multiples"). We use a generalized Titius-Bode relation to predict the periods of 228 additional planets in 151 of these Kepler multiples. These Titius-Bode-based predictions suggest that there are, on average, ~2 planets in the habitable zone of each star. We estimate the inclination of the invariable plane for each system and prioritize our planet predictions by their geometric probability to transit. We highlight a short list of 77 predicted planets in 40 systems with a high geometric probability to transit, resulting in an expected detection rate of ~15%, ~3 times higher than the detection rate of our previous Titius-Bode-based predictions.

Evaluation of global vertical illuminance and irradiance models against data from Yongin, South Korea

It is crucial to acknowledge the quantitative data on daylight illuminance and solar irradiance from a vertical plane or an incline plane for architects and architectural engineers in order to design energy efficient buildings and to create luminous environments. Also, the information of diffuse skies and the direct sun light from the vertical plane are essential in creating a comfortable working environment and a healthy indoor environment. This paper presents an evaluation of six inclined illuminance and irradiance models for Korea using two year of measured daylight weather data. In addition, a global vertical illuminance model for Korea was proposed. The evaluation was carried out for both global vertical illuminance and irradiance. The performance of all models was assessed with two common statistical parameters: the relative root mean square error (RMSE) and the relative mean bias error (MBE). As a result, all six models show high MBE and RMSE values and percentages for north-facing surfaces. On the other hand, predictions for south-facing surfaces produce good agreement with measured data. Kong's model shows the best prediction for global vertical illuminance as compared to those by Perez, Klucher, Hay, Temps–Coulson and Muneer. It is expected that the proposed model can be used as the basic data to maximize energy saving and to promote a pleasant building environment in Korea.