Two-dimensional Classification Research Articles

Análise da complexidade de itens do ENADE à luz da Taxonomia de Bloom Revisada: contributos ao ensino de Física

A avaliação do Ensino Superior no Brasil é realizada pelo Sistema Nacional de Educação Superior (SINAES), que tem como um de seus indicadores o Exame Nacional de Desempenho dos Estudantes (ENADE). Neste trabalho foram analisados 120 (cento e vinte) itens objetivos e discursivos das provas ENADE para a Licenciatura em Física, nas edições de 2005, 2008, 2011 e 2014, buscando estudar a sua complexidade pela Taxonomia de Bloom Revisada (TBR). A TBR apresenta uma proposta de classificação bidimensional cruzando uma dimensão do conhecimento, isto é, “o que” o estudante deve saber para resolver a tarefa proposta, com os processos cognitivos envolvidos na resolução da tarefa proposta, refletindo “como” o problema é resolvido. Para a TBR o conhecimento pode ser compreendido nas dimensões: efetivo, conceitual, procedural e metacognitivo, que tratam, respectivamente, de conhecimentos básicos de terminologia, conhecimentos de conceitos, conhecimentos de metodologia procedimental e conhecimentos reflexivos e analíticos sobre a escolha para resolver a tarefa. Os processos cognitivos, apresentados por verbos na TBR, classificam quais habilidades o estudante requer para resolver a tarefa: lembrar, entender, aplicar, analisar, avaliar e criar. Para discriminar as capacidades requeridas nos itens discursivos, foram observados os padrões de respostas divulgados pelo MEC e, nos itens de múltipla escolha, a nossa resolução das questões. Em seguida, os itens foram alocados na tabela bidimensional proposta pela TBR, a qual nos fornece um panorama de cada prova. Observa-se na dimensão do conhecimento que apenas 17 (14%) dos itens avaliados nas quatro edições do exame estão no domínio do conhecimento efetivo, enquanto que 103 (86%) dos itens requerem os domínios do conhecimento conceitual e procedural (procedimental), os quais exigem níveis de maior complexidade. Entende-se tal resultado como compatível com o papel estratégico do ENADE como indicador balizador da qualidade do Ensino Superior Brasileiro. Pretende-se ampliar a atualização de docentes de Física do ensino superior acerca do Exame, possibilitando-lhes refletir sobre os aspectos da cognição envolvidos no ENADE, na perspectiva proposta pela TBR, incorporando seus pressupostos em sua práxis.

A novel classification system for the evaluation and reconstruction of oral defects following oncological surgery.

Accurate evaluation of oral tissue defects following oncological surgery is necessary for the subsequent reconstruction. However, there is currently no effective classification system for oral defects in the clinical setting. The present study therefore developed a clinical classification system for the evaluation and reconstruction of oral defects. A retrospective cohort study was performed. A two-dimensional classification system based on coronal computed tomography/magnetic resonance imaging was developed and validated by 145 cases with oral defects. Oral defects could be classified into 6 types (I–VI) horizontally and 2 classes (a and b) vertically. The proportion of the various types was as follows: Type I, 35.9%; type II, 21.4%; type III, 23.4%; type IV, 4.8%; type V, 2.1%; and type VI, 12.4%. Among them, 91 cases (62.8%) were class a and 54 cases (37.2%) were class b. Type Ia-Va represented the unilateral 1–5 subsites involving superficial oral defects without mandibular continuity destruction (88 cases, 60.7%). Type Ib-Vb (+M) represented the unilateral 1–5 subsites involving deep oral defects with segmental mandibular continuity destruction (38 cases, 26.2%). Type I–V (+S) represented the unilateral through and through oral defects with cheek skin involvement (10 cases, 6.9%). Type VI represented bilateral oral defects (18 cases, 12.4%). The present classification system for the evaluation of the oral defects was simple and practical, and could identify the common types of oral defects and guide the reconstruction.

Two-dimensional active raypath separation using examination of the roots of the spectrum polynomial.

The application of the root multiple signal classification algorithm for raypath separation was motivated by the dramatic reduction in processing time of the multiple-signal classification algorithm. However, the algorithm provides classification only in the direction of the arrival domain and fails to separate raypaths arriving at the array with similar directions of arrival. Moreover, for many applications in shallow water (such as ocean acoustic tomography and active sonar), the emitted signal is known and can be used as a priori information to improve the resolution. Thus, in this study, a two-dimensional active wideband classification algorithm is developed using the examination of the roots of the spectrum polynomial in the angle versus time domain. A two-step strategy is developed to enable extension to the two-dimensional case. The results of simulations confirm that the proposed algorithm achieves almost identical resolution as the existing two-dimensional algorithms while offering a significant reduction in computation time.

Real-Valued 2D MUSIC Algorithm Based on Modified Forward/Backward Averaging Using an Arbitrary Centrosymmetric Polarization Sensitive Array.

Two-dimensional multiple signal classification (MUSIC) algorithm based on polarization sensitive array (PSA) has excellent performance. However, it suffers a high computational complexity due to a multitude of complex operations. In this paper, we propose a real-valued two-dimensional MUSIC algorithm based on conjugate centrosymmetric signal model, which is applicable to arbitrary centrosymmetric polarization sensitive array. The modified forward/backward averaging, which can be applied to the PSA, is presented. Hence, the eigen-decomposition analysis process and spectrum function computation are converted into real domain, prominently reducing the computational complexity. Then, the direction-of-arrival (DOA) estimation is decoupled from the polarization parameter estimation so that the four-dimensional spectral peak search process is avoided. The theoretical computational complexity is discussed and the Cramer-Rao bound (CRB) of DOA estimation is derived in this paper. The simulation results indicate that the proposed algorithm achieves superior accuracy in DOA estimation and has low computational complexity.

Towards a Taxonomy of International Competitiveness

Purpose: A wide range of approaches to defining, modelling, and measuring international competitiveness can be found in the scholarly literature across various fields of management and economics. Such number of perspectives enhances scientific research, but confuses public debate. Despite certain definitional ambiguities, there is a consensus that international competitiveness is a multifaceted concept that should be analysed at different levels of aggregation: company level (micro), industry/cluster level (mezzo) and national level (macro). This paper addresses international competitiveness at all three levels and tracks the interlinkages between them with the aim to find a common ground for understanding this economic phenomenon in a systemic perspective: as a complex whole. Methodology: The paper constitutes an in-depth literature review, forming a basis for a new approach to categorizing the main perspectives on international competitiveness. A synthesis of the latest international competitiveness literature sources has been performed in order to categorize the existing approaches to defining, modelling, and measuring international competitiveness. Following Chandhuri’s and Ray’s (1997) two-dimensional classification approach (the level of analysis and the variable), the paper introduces new insights into the existing taxonomy of international competitiveness. Findings: Based upon the developed taxonomy, the paper offers an interdisciplinary, multi-layered model of international competitiveness. Originality: The offered findings enhance the active shaping of modern competitiveness research directions to support the competitiveness policy on the regional and national level.

Cognitive FDA‐MIMO radar for LPI transmit beamforming

Active radar is vulnerable to illegal eavesdroppers due to its high-gain beam-scanning signals. To reduce active radar visibility and enhance its low probability of intercept (LPI) capability, this study proposes a cognitive LPI transmit beamforming scheme using frequency diverse array (FDA) and multiple-input multiple-output (MIMO) hybrid array antenna. The achievement of LPI is due to the unique range-angle-dependent transmitting beampattern of FDA-MIMO radar, which minimises the beam power at the target location to reduce its visibility and simultaneously maximise the power at the radar receiver without degrading the radar detection performance. Furthermore, the FDA-MIMO radar operates in a cognitive way: the receiver estimates the target range and the direction of arrival with a two-dimensional multiple signal classification algorithm, and feedbacks their estimates to the transmitter to update the FDA-MIMO transmit beamforming. As the transmit beamforming optimisation is non-convex problem, the authors propose three methods, namely linear combination, non-linear combination and closed form solution. All the proposed methods are verified by simulation results.

Prediction of pesticide acute toxicity using two-dimensional chemical descriptors and target species classification

Previous modelling of the median lethal dose (oral rat LD50) has indicated that local class-based models yield better correlations than global models. We evaluated the hypothesis that dividing the dataset by pesticidal mechanisms would improve prediction accuracy. A linear discriminant analysis (LDA) based-approach was utilized to assign indicators such as the pesticide target species, mode of action, or target species - mode of action combination. LDA models were able to predict these indicators with about 87% accuracy. Toxicity is predicted utilizing the QSAR model fit to chemicals with that indicator. Toxicity was also predicted using a global hierarchical clustering (HC) approach which divides data set into clusters based on molecular similarity. At a comparable prediction coverage (~94%), the global HC method yielded slightly higher prediction accuracy (r2 = 0.50) than the LDA method (r2 ~ 0.47). A single model fit to the entire training set yielded the poorest results (r2 = 0.38), indicating that there is an advantage to clustering the dataset to predict acute toxicity. Finally, this study shows that whilst dividing the training set into subsets (i.e. clusters) improves prediction accuracy, it may not matter which method (expert based or purely machine learning) is used to divide the dataset into subsets.

A Two-Dimensional Webpage Classification Model

Regarding the webpage classification topics, most classification mechanisms may lack of consideration from the webpage article writer's perspective and the display characteristics of the webpage (color, graphic layout). Hence, this paper develops a Two-dimensional Webpage Classification model to analyze the webpage textual information and display characteristics from the perspectives of webpage users and designers. This model is consisted of the Webpage Block Distribution Analysis (WBDA) module, Webpage Emotion Category Determination (WECD) module and Webpage Specialty Category Determination (WSCD) module. Firstly, in WBDA module, the user and designer habits (such as the web browsing movement and the writing perspective of webpage) should be considered by combining with the eye movement tracking and tag-region judgment to determine the critical blocks and information of the webpage. Secondly, in WECD module, the webpage color codes are acquired to calculate the major colors of the webpage, and further determine the emotional category of webpage. Thirdly, the WSCD module analyzes the webpage textual information by integrating the keyword acquisition technology to identify the specialty category of the webpage. After that, the Two-dimensional category of the webpage can be obtained. In addition, this paper develops a web-based system accordingly for case verification to confirm the feasibility of the methodology. The verification results show that firstly for webpage emotion category judgment when 128 webpage files for training are imported into this system, the respondent's emotion evaluation score is increased to above Level 5 and the system recommendation success rate is increased to 75.78%. Secondly, for specialty category determination, when system uses 1010 to 1120 webpage files for training, the system performance can be increased to above 80%. Hence, the developed system has a high-performance level in webpage emotion category and specialty category determination. That is, this paper proposes a methodology of Two-dimensional Webpage Classification to classify the webpage file information contents and the effects on the emotions of the demanders to assist webpage providers in providing webpage suitable for demanders with the generated two-dimensional information of the webpage.

Storm Labeling in Three Dimensions (SL3D): A Volumetric Radar Echo and Dual-Polarization Updraft Classification Algorithm

This study presents a new storm classification method for objectively stratifying three-dimensional radar echo into five categories: convection, convective updraft, precipitating stratiform, nonprecipitating stratiform, and ice-only anvil. The Storm Labeling in Three Dimensions (SL3D) algorithm utilizes volumetric radar data to classify radar echo based on storm height, depth, and intensity in order to provide a new method for updraft classification and improve upon the limitations of traditional storm classification algorithms. Convective updrafts are identified by searching for three known polarimetric radar signatures: weak-echo regions (bounded and unbounded) in the radar reflectivity factor at horizontal polarization ([Formula: see text]), differential radar reflectivity ([Formula: see text]) columns, and specific differential phase ([Formula: see text]) columns. Additionally, leveraging the three-dimensional information allows SL3D to improve upon missed identifications of weak convection and intense stratiform rain in traditional two-dimensional classification schemes. This study presents the results of applying the SL3D algorithm to several cases of high-resolution three-dimensional composites of NEXRAD WSR-88D data in the contiguous United States. Comparisons with a traditional algorithm that uses two-dimensional maps of [Formula: see text] are also shown to illustrate the differences of the SL3D algorithm.

What makes continued mobile gaming enjoyable?

Earlier mobile game studies have largely focused on the pre-adoption phase while ignoring the post-adoption behaviors. Additionally, while the intrinsic factor of enjoyment is often considered important in affecting game play, little research has attempted to understand its drivers. To fill these gaps, we examine the role of enjoyment as a motive for continual mobile game use, and the key antecedents of enjoyment. Applying our two-dimensional classification of artifact-related attributes, we adopt game design attributes of challenge, variety, novelty, and design aesthetics; and playability attributes of ease of use, and interactivity, and measure their impact on enjoyment, and its effect on continuance intention. The model is tested against 207 actual users of various mobile games. Structural equation modeling (SEM) is employed for data analysis. The findings put ease of use, novelty, design aesthetic, and challenge under the spotlight. We conclude that continual mobile game use is strongly driven by enjoyment, which in turn is primarily driven by the system's capacity of regeneration and visually attractive and easy-to-use interface. The implications are discussed in the paper.

Auditory "bubbles": Efficient classification of the spectrotemporal modulations essential for speech intelligibility.

Speech intelligibility depends on the integrity of spectrotemporal patterns in the signal. The current study is concerned with the speech modulation power spectrum (MPS), which is a two-dimensional representation of energy at different combinations of temporal and spectral (i.e., spectrotemporal) modulation rates. A psychophysical procedure was developed to identify the regions of the MPS that contribute to successful reception of auditory sentences. The procedure, based on the two-dimensional image classification technique known as "bubbles" (Gosselin and Schyns (2001). Vision Res. 41, 2261-2271), involves filtering (i.e., degrading) the speech signal by removing parts of the MPS at random, and relating filter patterns to observer performance (keywords identified) over a number of trials. The result is a classification image (CImg) or "perceptual map" that emphasizes regions of the MPS essential for speech intelligibility. This procedure was tested using normal-rate and 2×-time-compressed sentences. The results indicated: (a) CImgs could be reliably estimated in individual listeners in relatively few trials, (b) CImgs tracked changes in spectrotemporal modulation energy induced by time compression, though not completely, indicating that "perceptual maps" deviated from physical stimulus energy, and

Digital imaging 2D and 3D particle assessment using a flat-bed scanner

Aggregate particles are the main component of concrete and macadam bound highway pavements. Aggregate shape, texture and angularity characteristics are highly influential on production and performance in service of concrete and macadam, as well as influencing production costs. Although there are numerous methods of assessing particle shape, dating back more than 100 years, there is still no definitive three-dimensional (3D) means of testing and characterising particle shape for aggregates used in construction. This paper provides a review of various shape factors as well as two-dimensional (2D) shape classification charts. A method is described utilising a flat-bed desktop scanner to provide 2D images of aggregate particles, which provide an efficient and rapid means of comparing any aggregate source shape characteristics against calibrated visual shape charts. The method uses three particle shape factors: percentage concavity, aspect ratio and Riley circularity. The method has been extended by suspending, rotating and scanning aggregate particles to provide binary silhouette images at rotation intervals in all three orthogonal axes; collectively, these can provide a 3D particle shape classification. This method could be used to classify aggregate shape, as an on-going check on shape variation, and as a means of comparing and assessing potential recycled materials for construction use.

The development of a culture of problem solving with secondary students through heuristic strategies

The article reports the results of a longitudinal research study conducted in three mathematics classes in Czech schools with 62 pupils aged 12–18 years. The pupils were exposed to the use of selected heuristic strategies in mathematical problem solving for a period of 16 months. This was done through solving problems where the solution was the most efficient if heuristic strategies were used. The authors conducted a two-dimensional classification of the use of heuristic strategies based on the work of Polya (2004) and Schoenfeld (1985). We developed a tool that allows for the description of a pupil’s ability to solve problems. Named, the Culture of Problem Solving (CPS), this tool consists of four components: intelligence, text comprehension, creativity and the ability to use existing knowledge. The pupils’ success rate in problem solving and the changes in some of the CPS factors pre- and post-experiment were monitored. The pupils appeared to considerably improve in the creativity component. In addition, the results indicate a positive change in the students’ attitude to problem solving. As far as the teachers participating in the experiment are concerned, a significant change was in their teaching style to a more constructivist, inquiry-based approach, as well as their willingness to accept a student’s non-standard approach to solving a problem. Another important outcome of the research was the identification of the heuristic strategies that can be taught via long-term guided solutions of suitable problems and those that cannot. Those that can be taught include systematic experimentation, guess–check–revise and introduction of an auxiliary element. Those that cannot be taught (or can only be taught with difficulty) include the strategies of specification and generalization and analogy.

과학고 자기주도학습전형 쟁점 연구

본 연구는 과학고 자기주도학습전형에서의 쟁점항목을 탐색하고 이에 대한 중요도를 분석하여 자기주도학습전형 진행의 시사점을 도출하는 것을 목적으로 수행되었다. 이를 위해서 문헌조사와 과학고 입학담당관(혹은 입학사정관) 면담 등을 통해 예비-잠정쟁점사항을 추출한 후 교육전문가 및 현장전문가의 검토를 받았다. 그리고 전형전문가 델파이 조사를 거쳐서 내용타당도를 검정한 후 쟁점항목 96개를 도출하여 설문도구를 개발하였다. 이를 바탕으로 설문조사를 실시하였다. 설문조사는 20개 과학고의 입학담당관들을 대상으로 이메일을 이용하였다. 설문의 내용은 개별 쟁점항목에 대하여 입학담당관들의 인식의 중요도와 개별 학교에서의 발생유무였다. 수집된 자료들에 대한 쟁점항목 중요도와 발생 빈도수를 통계 처리하여 두 요인의 평균값을 기준으로 상하로 구분한 후 2차원 분류표에 유형별로 배치하였다. 이 과정에서 도출된 4가지의 유형별 쟁점은 다음과 같다. 첫 번째 유형은 개별 쟁점들의 중요도와 발생빈도수에 대한평균이 전체의 평균보다 모두 낮은 28개의 항목으로 이들은 경미한 쟁점에 해당한다. 두 번째 유형은 전체 평균보다 개별 쟁점의 중요도 평균은 높지만 발생빈도수 평균은 낮은 29개 항목의 잠재적 쟁점이다. 세 번째는 평이한 쟁점으로 이것은 두 요인에 대한 전체 평균에 비해 개별 쟁점의 중요도 평균은 낮지만 발생빈도수는 높은 17개 항목이다. 마지막으로 주요 쟁점이다. 이것은 두 요인에 대한 개별 쟁점항목들의 평균이 전체 평균보다 모두 높은 22개의 항목이다. 본 연구결과로 도출된 자기주도학습전형 쟁점항목들의 종류와 유형들은 이 전형을 실시하는 학교에서 전형현장에서 활용될 수 있을 것으로 보며, 특히 주요 쟁점에 대해서는 전형계획 수립 과정에서 적극 고려되어야 할 것이다. This study is to discover the diverse issues related to Self-Directed Learning Screening (SDLS) and draw implications by analyzing its critical points. Using content analysis and interviews with admission officers, tentative issues were finalized and reviewed by researchers and educators. A Survey was developed based on the 96 issues after having evidence of content validity using the Delphi method. To conduct survey, e-mails were sent to admissions officers in twenty science specialized high schools. They were asked to response to questions about perceptions of critical issues and if there are any issues in their schools. Using mean scores of two factors based on its critical issues and frequencies, a two-dimensional classification table for each type was presented. Four critical issues for each type were discovered. The first type indicates minor issues that include 28 items that were less than the overall mean scores in terms of critical issues and its frequencies. The second type indicates tentative issues that include 29 items that were greater than the mean score in critical issues but less in its frequencies. The third type indicates general issues that include 17 items that were less than the mean score in critical issues but greater in its frequencies. The last type indicates critical issues that include 22 items that were greater than the mean scores in two factors. The discovered results of critical issues and its types in this study can be considered a core part of the screening process in schools, especially, critical issues should play an important role in the process of admission screening planning.

An improved two-dimensional multiple signal classification approach for impact localization on a composite structure

Efficient impact monitoring techniques are important to be researched to ensure the safety of in-service composite structures. Multiple signal classification–based method is a new promising method. This method uses small aperture sensor array arrangement instead of sparse sensor arrangement. It has the advantage of easy sensor array arrangement. By processing the whole sensor array outputs using the multiple signal classification algorithm, transfer function and material property of the structure are not needed. Although some researches have shown the potential of this new method, most of the current researches have been performed based on the far-field assumption on aluminum structures. In engineering applications, composite structures are the main structures which need impact monitoring. Deep research needs to be addressed. Aiming at these problems, an improved two-dimensional near-field multiple signal classification processing algorithm is presented for impact localization on composite structure in this article. The proposed method can simultaneously estimate the impact occurring direction and distance. A uniform carbon fiber composite plate and a real aircraft oil tank made of carbon composite structure with varied thickness are adopted to evaluate the presented method. To deal with the anisotropy performance of the complex composite, the two-dimensional multiple signal classification processing algorithm is also improved by taking into account the existing anisotropy performance.

The Missing Meditatio

Summary This work describes the contributions of Leonhard Euler (1707–1783), the 18th-century physicist and mathematician, to the fields of articulatory and experimental phonetics. First the authors provide evidence for Euler’s role in establishing the St. Petersburg Academy prize of 1780. Next, they consider a short and posthumously published work of Euler, the Meditatio de formatione vocum. It is shown that the Meditatio represents an early attempt to compare vowels in several languages, and includes a two-dimensional classification of vowels which anticipates in many ways the International Phonetic Alphabet vowel chart.

Study of amphiphilic properties of amine- and oligo(ethylene glycol)-containing (meth)acrylic monomers

The two-dimensional classification was applied to the estimation of hydrophilic–hydrophobic properties of four amine-containing (meth)acrylic monomers, 2-hydroxyethyl methacrylate, and four oligo(ethylene glycol) methacrylates of various degrees of the ethoxylation. For the monomers, the standard free energy of partition between water and organic phase and standard free energy of adsorption of monomers at the interface were determined in hexane/water systems. Based on the standard free energy of partition and standard free energy of adsorption amphiphilic properties of the monomers were evaluated in terms of the two-dimensional diagram. The monomers were divided into three groups with respect to the position of the monomers in the diagram. These positions are connected with the nature of the substances. The classification allows estimating of monomers partition between interfaces or bulk phases in systems with developed interfaces.

The performance of high-tech companies: The evidence from the Visegrad Group

The purpose of this paper is to analyse the financial performance of large high-tech companies (both product- and service-oriented) in the Visegrad Four (V4) countries. We concentrate on the five-year period from 2007 to 2011. As the performance indicators, the most frequent financial measures – liquidity, profitability and solvency ratios – are used. We use two-dimensional classification to analyse the financial situation of large high-tech companies among the countries in the Visegrad Group. The research sample includes 139 Czech, 68 Hungarian, 270 Polish and 37 Slovak large high-tech companies. The results from this study indicate that the profitability, liquidity and solvency ratios increased in large manufacturing high-tech companies within the investigated period in the Czech Republic and Slovakia, while in Poland and Hungary the situation in the manufacturing sector was exactly the opposite. In terms of the service high-tech sector in the Visegrad countries, the ratios are volatile with a decreasing tendency. The results also indicate that the high-tech sector consists of companies with high liquidity, rather than companies with strong profits. Finally, correlation and regression analyses are conducted to examine the nature and extent of the relationship between profitability and liquidity.

Astaxanthin diferulate as a bifunctional antioxidant

Astaxanthin when esterified with ferulic acid is better singlet oxygen quencher with k2 = (1.58 ± 0.1) 1010 L mol− 1s− 1 in ethanol at 25°C compared with astaxanthin with k2 = (1.12 ± 0.01) 109 L mol− 1s− 1. The ferulate moiety in the astaxanthin diester is a better radical scavenger than free ferulic acid as seen from the rate constant of scavenging of 1-hydroxyethyl radicals in ethanol at 25°C with a second-order rate constant of (1.68 ± 0.1) 108 L mol− 1s− 1 compared with (1.60 ± 0.03) 107 L mol− 1s− 1 for the astaxanthin:ferulic acid mixture, 1:2 equivalents. The mutual enhancement of antioxidant activity for the newly synthetized astaxanthin diferulate becoming a bifunctional antioxidant is rationalized according to a two-dimensional classification plot for electron donation and electron acceptance capability.

Classification of the Aging Lips: A Foundation for an Integrated Approach to Perioral Rejuvenation.

Although perioral aging is highly individual with several distinct processes taking part simultaneously, there is scarce systematic information which helps to indicate the right rejuvenation approach among the multitude of proposed procedures. Existing data about perioral aging has not yet been transformed into a consistent therapeutic concept. The intention of this study was to provide a simple, yet reproducible classification and to offer appropriate rejuvenation approaches. To identify reliable and constant landmarks of the ongoing process of perioral aging, 462 perioral photo documentations were morphometrically analyzed. Based upon the identified landmarks a two-dimensional classification was developed. The classification was validated by three plastic surgeons. Inter- and intra-rater reliability was calculated using Cohen's kappa coefficient. Perioral aging can be broken down into changes of the lip shape and changes of the lip surface. Both processes can be classified into three stages each: Lip shape according to the shape in profile view, the lip length in relation to the frontal incisors, and the degree of vermilion inversion. Lip surface according to the presence and degree of radial wrinkles and the visibility of the structural elements Cupid's bow, philtrum, and white roll. Inter-observer reliability was rated very good (kappa values between 0.819 and 0.963) and perfect for intra-observer reliability (1.0). A better understanding of perioral aging leads to a simple classification for the aging lips. Using the classification helps to tailor an appropriate treatment to the individual patient and aids to achieve a natural rejuvenation result.