ACOUSTICS AND PERCEPTION OF SOUND IN EVERYDAY ENVIRONMENTS
Barbara Shinn-Cunningham
Boston University
677 Beacon St.
Boston, MA 02215
shinn@https://www.doczj.com/doc/883128607.html,
ABSTRACT
One aspect of hearing that has received relatively little attention by traditional psychophysicists is how echoes and reverberation in everyday spaces affect perception. In the ordinary world, echoes and reverberation are ubiquitous and influence the signals reaching the listener, the processing of these signals by the brain, and the resulting perception of both sound sources and the environment. Many aspects of the signals reaching the ear are altered or "distorted" by echoes and reverberation, including spectral content, interaural differences, and temporal structure. As a result, echoes and reverberation could influence many aspects of perception, including spatial hearing in direction and distance, speech intelligibility, and spatial unmasking. This paper reviews results from a number of studies examining how the acoustics of ordinary rooms affect various aspects of the signals reaching a listener's ears as well as resulting perception. While the acoustic effects of reverberant energy are often pronounced, performance on most behavioral tasks is relatively robust to these effects. These perceptual results suggest that listeners may not simply be adept at ignoring the signal distortion caused by ordinary room acoustics, but may be adapted to deal with its presence. These results are important for designing truly immersive spatial auditory displays, because they demonstrate the importance of reverberant energy for achieving a realistic, immersive experience.
1.OUR COMPLEX ACOUSTIC WORLD
Most psychology and neuroscience textbooks discuss auditory perception as if the only acoustic energy reaching a listener arrives directly from a source, ignoring the fact that much of the energy arrives indirectly, reflecting off the many objects in the environment. In fact, in decoding sound, the auditory system deals with a much more complex and interesting set of problems than the simplified textbook view suggests, and does so efficiently and elegantly.
For instance, textbooks treat the computation of sound source location as a relatively straightforward problem, as if the auditory system simply extracts basic acoustic cues (such as interaural differences and spectral cues) and estimates the location of a source from these cues (e.g., see [1, 2]). This analysis assumes that acoustic cues that arise for a source from a particular location do not vary with the environment and virtually ignores the computation of source distance. However, in our everyday lives, the very cues used to compute source position depend not only on the sound that reaches the ears of the listener directly, but on sound that is reflected off of all of the objects in the environment, including walls, floor, furniture, etc. As a result, the acoustic cues used to determine source position depend not only on the location of the source relative to the listener, but also on the acoustic environment and the location and orientation of source and listener in the environment [3, 4]. It is well known that the presence of reverberant energy provides information about acoustic source distance [5-15], but little is known about listeners compute source distance based on the signals reaching their ears [15, 16].
Similarly, most discussions of speech recognition focus on how to decode the signal emitted by a talker, not the actual signal reaching the receiver (e.g., see [17]). Most automatic speech recognition systems are designed to interpret clean speech (without any reverberation) and therefore tend to perform poorly in ordinary reverberant environments. In contrast, the ability of human listeners to understand speech is relatively robust in the presence of modest amounts of reverberant energy [18-20].
This paper reviews a number of studies investigating how reverberation in a moderate-sized room influences acoustics and perception. Results suggest that the presence of echoes and reverberation (referred to jointly as “reverberation”throughout the remainder of this paper) significantly distorts many of the acoustic cues thought important for spatial hearing and other perceptual tasks. However, listeners are not only adept at making accurate judgments in ordinary reverberant environments, they are in fact adapted to the presence of reverberation and benefit from its presence in many ways. These results underscore the importance of simulating room acoustics in order to create realistic and natural three-dimensional spatial auditory displays.
The initial studies reviewed in this paper focus on studying the acoustics of a moderate-sized classroom (dimensions of 5 m x 9 m x 3.5 m). Of course, the effects of reverberation vary dramatically with environment. However, studying in depth what happens due to the reverberation present in one particular environment provides general insights into both acoustic and perceptual effects of reverberation in other relatively small rooms.
In order to understand how the effects of reverberation are influenced by listener location, these studies compare effects for four different locations of the listener in the room, depicted schematically in Figure 1. In the center location, there are no reflective surfaces near the listener. In the left location, the listener’s left side is very close to one wall. In the back location, the listener’s back is to the wall. Finally, in the corner location, both the listener’s left side and back are near a wall. For all of these listener locations, a sound source
Figure 2: Cross-correlation analysis of left and right ear signals as a function of source location and listener location. Top row shows the normalized cross-correlation peak amplitude. Bottom row shows the interaural time delay of the peak.
was presented from a range of sources in the front right quadrant of space (depicted in gray in Figure 1). In some cases, acoustic measurements were used to analyze how listener location influenced the signals reaching the ears. In other cases, perceptual studies were performed in the actual room. Finally, acoustic measurements were used to create realistic headphone-based simulations of the signals reaching the listener in order to study the perceptual effects of realistic reverberation with carefully-controlled stimuli.
2. ACOUSTIC EFFECTS OF REVERBERATION Reverberation influences nearly all acoustical attributes of the signals reaching the ears of the listener, including temporal structure, spectral content, intensity, and interaural differences. Simple physics dictates that the magnitude of all of the acoustical effects of reverberation varies inversely with the direct-to-reverberant energy ratio (D/R). The direct sound level reaching the ear varies dramatically with the position of the sound source relative to the listener; as a result, D/R changes systematically with source position [21-23]. The direct sound level decreases with the square of the distance from source to head; thus, D/R decreases and the effects of reverberation increase with distance [22]. As the sound source is moved laterally off the median plane, the direct sound level decreases at the far ear and increases at the near ear, an effect that is more pronounced at high frequencies and increases as the source approaches the head. Thus, the effects of reverberation vary with source laterality (and do so most strongly for sources near the listener), increasing at the far ear and decreasing at the near ear [22].
The location of the listener in the room also has a dramatic effect on the level and pattern of reverberation at the ears [4, 21-26]. For instance, when the listener is far from any walls, the steady-state effect of the reverberation is a distortion that is essentially independent from frequency to frequency; however, early, strong reflection (such as arise when a listener is seated close to a wall) lead to systematic distortions of acoustic spatial cues. When a listener is near a reflecting wall, the spectral content of the total signal reaching the listener is comb-filtered (due to frequency-dependent reinforcement and cancellation of the direct sound by the echo), producing notches in the spectra received at the ears that vary with listener position relative to the wall and
source position relative to the listener. Such comb-filtering also systematically distorts interaural differences.
Whether or not there are early, intense reflections, the overall effect of reverberation is to introduce variations in the interaural and spectral localization cues that govern localization perception, even though these acoustic effects are more pronounced when a listener is near a wall and when the source is far from the listener.
Figure 2 demonstrates how reverberation influences the interaural time difference (ITD) for different listener and source positions. Head-Related Transfer Functions (HRTFs)were measured for source locations in the horizontal plane in the front-right quadrant of space relative to KEMAR for the four listener locations shown in Figure 1. The center HRTF locations were time-windowed to generate pseudo-anechoic HRTFs. The left- and right-ear HRTFs for the resulting five sets of HRTFs (anechoic , center , back , left , and corner ) were bandpass filtered from 100 – 2000 Hz, cross-correlated, and then normalized by the energy in the bandpass-filtered left-and right-ear HRTFs. The main peak falling within the physiologically-plausible ITD range (-1 to +1 ms) was identified. The normalized peak magnitude (which has a maximum value of +1 by construct) is plotted in the top row of Figure 2; the corresponding ITD value is plotted in the bottom row of the figure.
In anechoic space, the peak correlation value decreases,albeit slightly, with source azimuth due to frequency-dependent filtering of the head. When the source is in front of the listener, the left- and right-ear signals are nearly identical;however, the similarity decreases with source azimuth. The general effect of reverberation (regardless of listener location)is to decrease the peak correlation value, an effect that grows with both source laterality and distance. The peak value also depends on the listener location in the room, and generally is smallest when the listener is in the corner or left room locations (where the head-shadowed ear receives early, intense
reflections).
Figure 1. Sketch of the four listener locations in the room (gray area shows source locations re:listener).
The effects of reverberation on binaural cues are dominated by the effect of reverberation on the ear with the smaller D/R. As a result, the D/R at the ear that is farther from the source determines how distorted ITD is by reverberation.This D/R decreases with source distance and azimuth and depends on listener position. In particular, when a listener has his shadowed ear facing a wall, peak correlation values are very low, especially for distant, lateral sources.
Despite the fact that the peak correlation value is dramatically affected by distance and listener location in the room, the ITD at which the peak occurs is relatively insensitive to reverberation (see bottom panels of Figure 2).
While the results in Figure 2 show the effects of reverberation on ITD only, similar effects arise for ILD and spectral shape cues; i.e., the primary effects of reverberation are to distort localization cues, and this distortion increases with source azimuth and distance as well as with the number of reflecting surfaces near the listener [23]. In addition, while the results reported in Figure 2 are from a manekin, similar measurements [23, 27] show that KEMAR results fall within the range of data taken with human subjects. Overall, these results suggest that listener location may not have a large impact on the average perceived location of a sound source,but that the reliability of judgments of location may degrade with reverberation.
3. SPATIAL HEARING
Based on acoustical measurements (like those shown in Figure 2), we did not expect to see large effects of reverberation on the perceived source location for sources within a meter of the listener when the listener is in the center of the classroom. In these conditions, D/R is relatively large,and the distortion of the acoustic cues for localization relatively small and random.
Our initial study of localization in a room [3, 28, 29]replicated an earlier study of three-dimensional sound localization of nearby sources in anechoic space [30] in a classroom. Subjects pointed to the perceived sound source location while in the center of the room, far from any reflective surfaces, and then repeated the experiment with a
large wallboard positioned to their side. We hypothesized that in the center condition localization performance would be nearly identical to that seen in the prior anechoic study;however, we expected performance to be worse when the wallboard was close to the listener. We found that distance localization was much better for both center and wallboard conditions than for the anechoic condition. For directional localization, response variability was slightly larger in both reverberant conditions than in anechoic conditions [3, 28, 29,31], but there was no systematic effect on signed localization error (which was near zero). Even more surprising, we found that response variability was generally smaller in the wallboard than the center condition. Further analysis suggested that this result was due to “room learning,” or an improvement in localization reliability with experience, that occurred during the center trials (which all subjects performed prior to the wallboard trials).
These findings are illustrated in Figure 3 for localization in elevation (results are similar for the left-right and distance dimensions) [29, 31]. In the figure, the mean, unsigned error (which, for these experiments, primarily reflects response variability since mean signed error is near zero) is plotted for each listener for the first and last 200 trials in the center and wallboard conditions (right side of figure) as well as for the original anechoic study (left side of figure). In the anechoic condition [30], there is no statistically-significant change in localization performance with experience; however, mean unsigned error decreases significantly with practice in the center condition. Furthermore, there is no statistically-significant change in performance when the wallboard is first put in place and no improvement between the beginning and end of the wallboard trials. These results indicate that performance improves with experience in a reverberant, but not anechoic, room (even without explicit feedback). Further,learning generalizes to conditions that differ acoustically,like conditions (e.g., from center to wallboard conditions).
Because this study confounds effects of “room learning”with acoustic effects due to the wallboard, we conducted a follow up study [27]. Using the same basic procedures,subjects performed four separate experimental sessions, each performed with the listener in a different location in the room (the locations shown in Figure 1:left , corner , wall , and back ).
We hypothesized that both the acoustic differences across the conditions and the room learning effect would influence results. Acoustical measurements show that distortions of spatial cues are greatest in the corner and smallest in the center locations [23, 24, 27]. Two subject groups performed the experiment; Group A performed the four sessions in the order center , back , left , corner , and Group B performed the sessions in the reverse order (corner , left , back , center ). We expected subjects from Group B, who started in the most difficult and ended in the easiest acoustic condition, to show a large improvement in localization from sessions 1 to 4. We expected subjects from Group A to show smaller changes from session 1 to session 4 because acoustic and room-learning effects opposed one another.
Figure 4 shows the variance in responses for individual subjects and the across-subject group average for both the left-right and distance dimensions. Subjects in Group B (who ended in the easiest acoustic condition) showed a large decrease in response variance from session 1 to session 4. In contrast, subjects in Group A, who heard the easiest acoustic condition first, showed no systematic change across
sessions.
Figure 3: Mean error in elevation (deg) for the first and final 200 trials in each condition of a localization pointing experiment. Each set of bars represents results from one subject. Error bars show standard error over the 200 trials.
These results support the idea that the acoustics at different listening positions in a room influence performance, with performance generally worse for the corner location than for the center location. However, the fact that performance also improves from session to session supports the conclusions of the earlier experiment, i.e., that there is some room learning in occurs when listening in reverberant settings, an that whatever subjects learn in one room position at least partially transfers to other room positions.
These experiments show that moderate amounts of reverberation have a relatively modest impact on sound localization, causing an increase in the variability of judgments of source direction and improving the ability to judge distance. Even more, listeners appear to adapt to the reverberation present in a particular room, becoming more and more accurate at localization with experience.
4. SENSITIVITY TO REVERBERATION PATTERN In addition to providing distance information,reverberation provides listeners with a sense of the room itself. For instance, a listener can easily tell the difference between the acoustic effects of being in a small, tiled bathroom and being in a large, heavily-carpeted living room.In fact, much of the work in the field of architectural acoustics focuses on determining what kind of room reverberation is subjectively desirable in a concert-hall setting. Whereas the usual goal in architectural acoustics is to determine what constitutes a “good” acoustic space for the average listener in the environment, we decided ask a slightly different question and measure sensitivity to differences in reverberation with changes in listener location in one particular room.
Listeners were asked to identify their room location from headphone simulations of sources at different azimuths and distances relative to the head. We hypothesized that the ability to judge room location would improve with source distance because the relative level of the reverberant energy in the signals reaching the listener increases with source distance. We expected source azimuth to have some impact because the levels and pattern of direct and reverberant energy also change with azimuth.
For each listener location, HRTFs were measured for nine source positions (all combinations of azimuths 0, 45, and 90oto the right and distances 0.15, 0.40, and 1 m). Noise samples were convolved with the set of 36 HRTFs (9 source locations
x 4 listener locations) to generate binaural stimuli. In order to remove gross intensity differences, these stimuli were normalized so that the right-ear signal in each binaural pair (i.e., the louder of the signals in the binaural pair for the tested source locations) had the same RMS value. On each trial, the listener identified the room location, after which they were provided with correct-answer feedback.
Subjects performed 36 blocks of trials. In each block, all trials simulated the same source azimuth and distance;differences from trial to trial were due primarily to changes in the reverberation pattern. Each block consisted of 32 trials (8presentations from each of the 4 room locations, in random order). Prior to each block of 32 trials, subjects could listen to presentations from each of the room locations as many times as they wished; testing began only when subjects felt ready to proceed. Subjects performed 12 blocks per experimental session, during which the source distance was held constant.The three source azimuths were presented in random order within each session (different orders for each day and subject), so that each day, a subject heard four consecutive blocks from the same source location followed by two sets of four blocks, each simulating a different source azimuth. To reduce any artifacts due to training, the first block in each condition are not analyzed in the results reported here.
Because we were primarily interested in how well subjects could tell listener locations apart, we analyzed T , the information transfer ratio, for each source location and subject (see [32]). In theory, T ranges between zero and one and is exactly equal to one if knowing the subject’s response perfectly predicts the stimulus presented. Low values of T arise when responses are independent of the stimulus. Figure 5 shows that in this experiment performance is relatively poor and individual differences large (e.g., T ranges from 0.1 – 0.7for 90? sources). There is a modest effect of azimuth:performance is slightly (but significantly) better for sources at 90?; however, distance caused no statistically-significant main effect on T (multi-way ANOVA analysis, p < 0.05).
In order to gain further insight into what the listeners could hear, T was analyzed for each pair of room locations
to
Figure 5: Information transfer rate T as a function of source azimuth for three source distances (Experiment 1). Across-subject means shown by solid lines (with standard error bars);open symbols are individual subject
results.
Figure 4: Variance in localization judgments as a function of experimental session for left-right (left) and distance (right). Group A started in the easiest acoustic condition and progressed to the most difficult; Group B did the reverse.
determine which pairs were relatively difficult to tell apart and relatively easy. T was computed for each room pair for each listener and source location. For each subject, these values were averaged across azimuth (which had little effect on the pairwise T ).
Figure 6 shows the across-subject mean and standard error of T for all room pairings and for each of the source distances.These results show that for nearby sources, all room pairings were roughly equally discriminable; however, as distance increased, performance for four room pairs increased while for two pairs it decreased. More specifically, at the 1 m source distance, subjects could not distinguish between the two locations in which neither ear faced a wall (center and back )or between the two locations in which the left ear faced a wall (corner and left positions); however, they rarely made confusions across these categories (e.g., they rarely confused center and corner locations).
A follow-up study comparing monaural and binaural performance suggests that listeners are actually better at judging the simulated listener location in the room when listening monaurally to the head-shadowed ear signal [33]. In other words, normal, binaurally listening actually decreases a listener’s ability to discriminate between different patterns of reverberation. This finding hints that monaural (possibly spectral) cues are the most salient acoustic cue that could be used in this task, but that binaural listening degrades the ability to use these cues, as if the system automatically combines the signals at the two ears in a way that factors out reverberation effects.
These results suggest that under normal listening conditions listeners cannot easily discriminate where they are in an everyday room from the signals reaching their ears. For the most distant sources tested, listeners have a modest ability to discriminate between room locations in which one ear faces a wall and those in which neither ear is facing a wall,but cannot discriminate within these categories. For nearer sources, listener have some ability to discriminate across all combinations of room locations, but are not particularly good
at discriminating any room pairs. It appears that the presence of very early, strong echoes (as occur when one ear faces the wall and the source is relatively distant) are easy to hear, but that other differences are difficult to discriminate. More generally, this study suggests that listeners are insensitive to many of the fine details in the pattern of echoes reaching the ears, as previously hinted by previous studies [9, 34-37]. In practical terms, the fact that listeners cannot reliably identify differences between different listener locations in a room demonstrates that simplified reverberation models may be sufficient for many spatial auditory displays.
5. SPEECH INTELLIGIBILITY AND SPATIAL
UNMASKING OF SPEECH Spatial hearing is not the only aspect of auditory perception influenced by reverberation; reverberation can have a dramatic impact on the temporal modulations in a signal. The signal reaching the ears is mathematically equivalent to the “clean” source signal convolved with the reverberant impulse response of the head and room. Because the room impulse often has a long temporal extent, there is a general tendency for reverberation to smear-out the energy in the original signal and reduce any envelope modulations present in the original signal [38, 39]. Unfortunately, the temporal modulations in speech are one of the primary sources of information about speech content; as a result, reverberation can degrade speech intelligibility [38, 40, 41].
In many cases a source of interest (the target) is heard at the same time as a competing sound (the masker). It is well known that in anechoic conditions, spatial separation of target and masker improves speech intelligibility. This effect (known as “spatial unmasking”) arises both from changes in the target and masker energy levels at the ears with spatial separation and from neural processing effects. In particular,spatial separation of target and masker generally increases the target-to-masker ratio (TMR) at one ear (the “better ear”) and decreases it at the other ear, leading to simple improvements in speech intelligibility due to changes in the TMR. However,listeners often perform better when listening to binaural presentations of spatially-separated target and masker than when listening to monaural presentations of the better-ear signal (e.g., see [42-48]), suggesting that binaural processing leads to further improvements.
Studies have shown that reverberation can decrease the contribution of binaural processing to spatial-unmasking [49-53]. However, in many of these studies, the reverberation presented was unnatural in its level and/or in its structure.Additionally, most of these studies were conducted using methods that make it difficult to tease apart what factors contributed to the observed results.
We have performed some preliminary studies to determine how moderate levels of reverberation (found in everyday rooms) influence both speech intelligibility and spatial unmasking of speech. We have shown [54] that the modest levels of reverberation arising at the ears of the listener in the center room position do not significantly degrade sentence intelligibility; indeed, in some cases, sentences presented with reverberation are more audible (and hence more intelligibility) than sentences presented without reverberation. In addition, these levels of reverberation do not destroy spatial unmasking effects, at least for the
spatial
Figure 6: Pairwise information transfer rate for all combinations of room locations averaged across subjects (with across-subject standard error). Room locations: -: center ; C: corner ; B:back ; L: left .
configurations of target and masker we tested in our initial studies [19].
More recently [20], we examined spatial unmasking of speech tokens consisting of CV and VC (V= /a/) tokens.Listeners performed a one-interval, nine-alternative, forced-choice experiment in which they identified which of the nine obstruent consonants /b,d,g,p,t,k,f,v,dh/ was presented, either in quiet or in the presence of a speech-shaped noise masker (equal to the average spectra of all target speech tokens). Five normal-hearing subjects were tested on both initial and final consonant identification.
KEMAR HRTFs were used to simulate the target and masker at different spatial locations in three different acoustic environments (anechoic and center conditions as in Figure 2,as well as a bathroom condition using HRTFs from a tiled bathroom that is roughly 4 m x 2.5 m x 3.5 m). Both target utterances and noise masker were simulated at a distance of 1m. The target was always simulated from in front of the listener (0°); the masker (when present) was simulated from either 0° or 45° to the right of the subject. Identification performance was measured as a function of TMR at the acoustically “better ear” to estimate the psychometric function. Subjects were tested binaurally and monaurally (better ear only) in quiet, with the masker in front of the listener and with the masker at 45?.
Figure 7 plots percent-correct identification scores for the monaural test conditions. The top panel plots percent correct as a function of TMR at the better ear (note that chance performance is 1/9 or 11%). The bottom panel plots the difference between performance for spatially-separated and spatially-coincident target and masker (note change in vertical scale). Because the simulated energy emitted from M was adjusted to fix the overall TMR to the desired value at the better ear, the effects of monaural spatial unmasking are reduced compared to what would happen if the simulated masker were displaced in location (i.e., we normalized the signals to remove gross level changes due to moving the masker). This normalization was undertaken in order to
emphasize the spatial unmasking effects in which we were most interested.
In general, the effect of the room reverberation was modest when listening in quiet; listeners were able to perform essentially equally well in all three room conditions. There is a consistent trend for performance to decrease with decreasing TMR. Furthermore, there is a strong interaction between reverberation and TMR; performance decreases with TMR most rapidly in the bathroom and least rapidly in anechoic space.
Much of the information about consonant identity is conveyed by acoustic cues in the 2 kHz region of the spectrum (e.g., see [48]). For a source off to the side, the head attenuates energy at frequencies above 1.5 kHz so that the TMR is generally frequency dependent. For the target and masker locations in the current study, the TMR is larger at higher frequencies than at lower frequencies when target and masker are spatially separated. Thus, even though the root-mean-square TMR is normalized, the TMR in the critical frequency region between 1.5- 5 kHz improves when target and masker are spatially separated. In the anechoic condition,improvements in TMR in this critical frequency region with spatial separation of target and masker may explain the observed improvement in performance for initial consonants in the separated condition. In the classroom there is consistent spatial unmasking due to changes in the TMR in the critical frequency region for both initial and final consonants. In the bathroom there is no spatial unmasking for final consonants; furthermore, for initial consonants there is actually ‘spatial masking:’ performance is worse when target and masker are spatially separated than when they are at the same location.
Figures 8 and 9 compare scores for binaural and monaural conditions. Although binaural performance is generally better than monaural performance, similar improvements occur when the target and masker are at the same locations and when they are in different location. In other words, there is essentially no spatial unmasking beyond monaural effects due to changes in TMR in the critical frequency region around 2 kHz.Although binaural processing does not contribute to the spatial unmasking of the tested consonants, binaural performance is generally better than monaural in both reverberant environments, regardless of whether target and masker are at the same or different locations. This finding is consistent with some previous studies of binaural and monaural speech discrimination of reverberant speech [50]and may be due to a statistical decorrelation of the signals at the two ears. Essentially, the two ear signals differ because the reverberation reaching the ears differs; thus, the two ear signals may effectively provide the listener with two independent looks at target and masker. The observed binaural advantage is very different from the binaural advantages normally discussed in the literature, as it does not appear to be due either to explicit comparisons between the signals at the two ears [48] or to attending to one particular spatial location [55-58].
The results of this study differ from those of our own previous studies using nearly identical procedures with sentences for targets, rather than consonants [19, 54, 59]. In these previous studies, we found significantly binaural contributions to speech intelligibility, but only when target and masker were spatially separated. Of course, there are a number of additional acoustic and conextual (e.g.
lexical,
Figure 7. Monaural performance for (a, c) initial and (b, d) final consonants. Bottom panels show effect of spatial separation (positive values indicate improvements with spatial separation).
syntactic) cues available in a sentence perception task compared to in a consonant identification task.
Taken together, these studies suggest that binaural processing advantages are present when listening in reverberant environments, and that the nature of these binaural advantages depends on the type of stimuli presented.For sentence materials, there are spatial-separation advantages that appear to be mediated by “traditional” binaural/spatial processing. However, for phoneme recognition, binaural contributions do not come about from spatial separation of target and masker, but from some other mechanism.
Results from studies of this type can be used guide the design of spatial auditory displays by helping to determine what amount of reverberation can be included (to improve realism, provide distance cues, etc.) without perceptually degrading the source signal or destroying important spatial unmasking effects.
6. SUMMARY
Acoustical analysis shows that ordinary room reverberation distorts all aspects of the signals reaching a listener’s ears.The acoustic effects of reverberation are significant even when the source is relatively close to the listener. However, the various perceptual studies reviewed here show that the human listener not only copes well with reverberation, but also even benefits from its presence in many cases.
Moderate levels of reverberation are critical for achieving a subjectively-realistic simulation of sound sources in three-dimensional space, increasing the externalization of the simulated sources and improving the ability of the listener to judge source distance. The reverberation levels arising in a moderate-sized room have only a minor degrading effect on directional hearing (most notably, by increasing response variability). In addition, experience in the room leads to improved localization performance even in the absence of feedback, as if listeners automatically and naturally adapt and adjust to reverberation and calibrate their perception to the levels of reverberation they hear. While listeners are sensitive to gross characteristics of the reverberation pattern reaching the ears, they are not particularly adept at discriminating between the exact timing and direction of the echoes reaching the ears. Finally, to a first-order approximation, the effect of moderate reverberation on speech intelligibility is to improve audibility of the speech signal without destroying the contribution of binaural processing and spatial separation.However, the combined effects of a competing source and reverberation do cause degradations that are worse than might be expected from independently considering the effects of noise and reverberation.
Further experiments of the type outlined here will help to determine how reverberation in natural environments affects both the signals reaching the ears and the processing of sound by the human observer. By using virtual spatial auditory displays to tease apart the influence of reverberation on perception, we will be able to design effective spatial auditory displays that provide realistic spatial percepts without degrading the information conveyed by the sound sources in the auditory display.
7. ACKNOWLEDGEMENTS
This project was supported by grants from the Air Force Office of Scientific Research, the National Science Foundation, and the Alfred P. Sloan Foundation. A number of students and colleagues assisted in collecting and analyzing the data reviewed herein, including Tara Brown, Doug Brungart,Scarlet Constant, Nat Durlach, Sasha Devore, Kosuke Kawakyu, Norbert Kopco, and Suraj Ram.
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Figure 8. Performance for initial consonants. (a,d) anechoic, (b, e) classroom, and (c, f) bathroom.Bottom panels show binaural advantage (binaural -
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Safe And Sound Taylor Swift I remember tears streaming down your face, 我曾记泪水流过你的面庞 When I said I'll never let you go. 当我说我不会让你离开的时候 When all those shadows almost killed your light, 当暗影几乎抹杀了你的光芒 I remember, you said "Don't leave me here alone.." 我曾记你说“别留下我孤单一人” But all that's gone and dead and past, tonight; 但就在今晚，所有的一切、死亡的威胁都会过去 Just close your eyes, 闭上你的双眼吧 The sun is going down. 日沉西山 You'll be alright, 你会安然无恙 No one can hurt you now. 此刻没人能再把你伤害 Come morning light, 黎明就要来到 You and I'll be safe and sound. 你我会安然无恙 Don't you dare look out your window, darling, 吾爱，别不敢看向窗外 Everything's on fire… 一切都在燃烧 The war outside our door keeps raging on. 战争在外面肆虐 Hold on to this lullaby; 继续哼唱你的摇篮曲吧 Even when the music's gone. 即便音乐已经远去 Just close your eyes, 闭上你的双眼吧 The sun is going down. 日沉西山 You'll be alright, 你会安然无恙
期刊影响因子的“含金量”是多少 这是一个以标准衡量的世界。既然吃饭都有米其林餐厅评级作为参考，更何况严谨的学术科研成果。 期刊影响因子长久以来被学术界视为一个重要的科研水平参考指标。在一本影响因子高的期刊发表论文，科研人员的科研能力和成果也更容易获得认同。然而，部分科学家已对这一指标能否真正反映单篇论文乃至作者学术水平提出质疑，加上每年发布这一指标的汤森路透公司在本月早些时候宣布把相关业务转售给两家投资公司，影响因子未来能否继续维持其「影响力」令人存疑。 广泛影响 根据汤森路透发布的信息，该公司已同意将旗下知识产权与科学业务作价３５．５亿美元出售给私募股权公司Ｏｎｅｘ和霸菱亚洲投资。这一业务包括了世界知名的科技文献检索系统「科学引文索引」（简称ＳＣＩ）以及定期发布的《期刊引证报告》，其中的期刊影响因子是一本学术期刊影响力的重要参考。 新华社记者就此事咨询了汤森路透，该公司一位发言人说，这一交易预计今年晚些时候完成，在此之前该公司还会继续拥有并运营这项业务，「我们将在不影响这项业务开展和质量的前提下完成交易」。 帝国理工学院教授史蒂芬·柯里接受记者采访时说，他对汤森路透用来计算期刊影响因子所使用的数据是否可靠本来就有一定顾虑，「我不确定汤森路透的这次交易是否产生影响，但这项业务的接盘方如果未来能够保证这方面的透明度也是一件好事」。 影响因子的计算方法通常是以某一刊物在前两年发表的论文在当年被引用的总次数，除以该刊物前两年发表论文的总数，得出该刊物当年的影响因子数值。理论上，一种刊物的影响因子越高，影响力越大，所发表论文传播范围也更广。鉴于全球每个科研领域中都有大量专业期刊，如果有一个可靠的指标能告诉研究人员哪个期刊影响力更大，他们就能更高效地选择在一个高质量平台上发表科研成果。 但这又引申出一个现象，即许多科研机构、高校甚至学术同行越来越依赖影响因子来评判一篇论文甚至作者本身的科研水平，进而影响他们的职称评定和获取科研项目资助等机会。 业内争议 这种过度依赖影响因子的做法引起不少业内争议。来自帝国理工学院、皇家学会等科研机构学者以及《自然》《科学》等期刊出版方的高级编辑，合作撰写了一份报告分析其中弊端，并提出相关改进方案。这篇报告已在近期被分享到一个公开的预印本服务器上供同行审阅。 报告分析了包括《自然》《科学》在内１１份学术期刊在２０１３年至２０１４年间所刊发论文被引用次数的分布情况，这些数据也您身边的论文好秘书：您的原始资料与构思,我按您的意思整理成优秀论文论著,并安排出版发表，企鹅1550116010自信我会是您人生路上不可或缺的论文好秘书被用来计算２０１５年相关刊物的影响因子。 报告作者发现，多数论文被引用次数都达不到发表它们的期刊的影响因子数值水平，比如《自然》在这期间所刊发论文中的７４．８% 在２０１５年获得的引用次数就低于这本期刊当年影响因子所显示的水平，《科学》的情况也类似。报告说，这主要是因为这些期刊中有一小部分论文被引用次数非常高，导致影响因子在均值计算过程中出现偏差。 报告详细描述了如何更准确地计算出期刊所刊发论文被引用次数的分布状况，并呼吁各家期刊将这些基础数据公布出来，减少学术界对影响因子的过度依赖。
2006年国内医学类核心期刊及影响因子列表 序号期刊名称被引频次影响因子预防医学、卫生学类 1、中国地方病学杂志1172 1.237 2、中华结核和呼吸杂志2829 1.228 3、中华流行病学杂志18750.904 4、中华传染病杂志9530.903 5、中华预防医学杂志9680.891 6、中国消毒学杂志4380.738 7、中国艾滋病性病5690.680 8、营养学报7730.632 9、中华实验和临床病毒学杂志5310.543 10、环境与健康杂志5620.490 11、卫生研究7510.465 12、中华劳动卫生职业病杂志6810.456 13、中国防痨杂志4730.414 14、中国卫生统计2930.393 15、中国食品卫生杂志2640.391 16、中国职业医学3860.341 17、中国学校卫生8520.312 18、中华卫生杀虫药械950.310 19、中国寄生虫病防治杂志4210.297 20、中国公共卫生16620.296 20、环境与职业医学2510.296 22、中国慢性病预防与控制4210.291 23、工业卫生与职业病3330.280 24、华南预防医学2300.236 25、疾病控制杂志2490.222 26、中国工业医学杂志3170.217 27、中国地方病防治杂志3510.210 28、解放军预防医学杂志2870.190 29、热带医学杂志1070.178 30、实用预防医学4420.158 31、现代预防医学4110.142 32、预防医学情报杂志2350.131 33、职业与健康3370.048 基础、医学综合类 1、中华医院管理杂志2015 1.556 2、中华病理学杂志1425 1.171 3、中华医学杂志3792 1.091 4、中国危重病急救医学16340.998 5、实用诊断与治疗杂志6900.997 6、中华麻醉学杂志14870.918 7、生理学报6970.851
Falling Slowly I don't know you But I want you All the more for that Words fall through me And always fool me And I can't react And games that never amount To more than they're meant Will play themselves out Take this sinking boat and point it home We've still got time Raise your hopeful voice you have a choice You've made it now Falling slowly, eyes that know me And I can't go back Moods that take me and erase me And I'm painted black Well,You have suffered enough And warred with yourself It's time that you won Take this sinking boat and point it home We've still got time Raise your hopeful voice you had a choice You've made it now Falling slowly sing your melody I'll sing along Ah,ah~ Call and l'll sing along 中文大意 缓慢落下 我不认识你 但却想和你在一起 更进一步的了解你 但却无法言说 总是欺骗我 我无法回应你 游戏永远只是游戏 终有一天会完结 乘着这只将要沉的船回家 我们还有时间
感官动词verbs of perception 感官动词表示人的感官动作，可作完全及物动词或不完全及物动词，如：listen to(听)，hear(听见)，see(看见)，watch(观看)，feel (感觉)等。 1感官动词 (A) 感官动词(及物动词)有： see/notice/look at/watch/observe/listen to/hear/feel(Vt)/taste(Vt)/smell(Vt) /touch(Vt) (B) 连缀动词(含感官不及物动词) be/get/become/feel/look/sound/smell/taste/seem/ appear/grow/turn/prove/go/run 2用法 一、look，sound，smell，taste，feel，这五个动词均可作连系动词，后面接形容词作表语，说明主语所处的状态。其意思分别为"看/听/闻/尝/摸起来……"。 除look之外，其它几个动词的主语往往是物，而不是人。【有关质疑：feel的意思：感到，一般指一个人用手去摸布料，西红柿等东西的感觉，参见下面例句2你们就理解了。】例如： 1.These flowers smell very sweet.这些花闻起来很香。 2.The tomatoes feel very soft.这些西红柿摸起来很软。 二、这些动词后面也可接介词like短语，like后面常用名词。例如： Her idea sounds like fun.她的主意听起来很有趣。 三、这五个感官动词也可作实义动词，除look(当"看起来……"讲时)只能作不及物动词外，其余四个既可作及物动词也可作不及物动词，此时作为实义动词讲时其主语一般为人。（和1有区别）例如: She smelt the meat.她闻了闻那块肉。 I felt in my pocket for cigarettes.我用手在口袋里摸香烟。 四、taste，smell作不及物动词时，可用于"taste / smell + of +名词"结构，意为"有……味道/气味"。例如: The air in the room smells of earth.房间里的空气有股泥土味。 五、它们(sound除外)可以直接作名词，与have或take构成短语。例如: May I have atasteof the mooncakes?我可以尝一口这月饼吗？ taste有品位，味道的意思。例： I don't like the taste of the garlic. 我不喜欢大蒜的味道。 She dresses in poor taste.她穿着没有品位。 look有外观，特色的意思。例： The place has a European look.此地具有欧洲特色。 feel有感觉，感受的意思 六、其中look，sound，feel还能构成"look / sound / feel + as if +从句"结构，意为"看起来/听起来/感觉好像……"。例如： It looks as if our class is going to win.看来我们班好像要获胜了. 七、感官动词+do 与+doing的区别： 感官动词see，watch，observe，notice，look at，hear，listen to，smell，taste，
提高学术期刊影响因子的途径 作者：李勤来源：《今传媒》 美国科技信息研究所所长尤金?加菲尔德首先用论文的被引证频次来测度期刊的影响力，1963年美国科技信息研究所正式提出和使用影响因子这一术语。期刊在某年的影响因子是指该刊前两年发表论文在统计当年被引用的总次数除以该刊前两年发表论文的总数。由影响因子的定义可知，期刊的影响因子反映在一定时期内期刊论文的平均被引率。影响因子的三个基本要素是论文量、时间和被引次数，也就是说，期刊所刊发论文的被引情况决定了该期刊的影响因子。总的说来，一篇论文的被引次数越多，说明它的学术影响力越大，同样也表明它的学术质量较高、创新性较强。因为影响因子高的期刊具有较广泛的读者群和比较高的引用率。影响因子的高低客观地反映了期刊和编辑吸引高质量稿件的能力。所以，我们在评价期刊时，影响因子为重要的评价指标之一。许多作者在投稿时，也将影响因子高的期刊作为投稿首选。图书馆或研究院、资料室在选择订阅期刊或优化馆藏期刊时，也把期刊的影响因子作为重要的参考标准之一。而且影响因子也是筛选中文核心期刊的一项重要指标。因此，作为期刊工作者，努力提高期刊的影响因子十分必要。分析学术期刊的计量指标情况，决定影响因子高低的因素通常有这样几点： 一、影响因子的影响因素 一是论文发表时滞。论文发表时滞(DPA)是指期刊论文的出版日期与编辑部收到该文章的日期之时间差，以月为单位。它是衡量期刊时效性的重要指标，与期刊的影响因子和被引频次有密切关系。因为在计算影响因子时，期刊被引频次中两年的时间限制可导致不同刊物中论文的被引证次数有较大的差异。出版周期短的刊物更容易获得较高的影响因子。因而在同一学科领域的研究论文，特别是研究热点领域内的论文，首先被公开发表的论文更有可能引起较大的影响或者被别人引证。 二是论文学术水平。论文的学术质量直接制约着期刊影响因子的提高。学术质量较高的论文，容易被同行认可，引用率自然就高，影响因子也高。相反，学术质量较差的论文，不会被同行认可，得不到同行研究者的重视，引用率自然就低，影响因子也较低。在各类文章中，具有原创性的学术论文常常被研究人员参考和引用。同时有争议的学术讨论更容易获得同行的广泛关注，而普通的介绍性论文则不太被人们关注。 三是参考文献的数量和质量。由于影响因子是根据期刊的引文计算出来的，通常参考文献的内容越新颖，信息质量越高，影响因子就越高。准确的参考文献有助于作者在有限的篇幅中阐述论文的研究背景及其相关的观点和论据。同时可以方便读者追溯有关的参考资料进一步研究问题。统计分析表明，期刊的影响因子主要取决于论文的平均引文数、引证半衰期及论文的被引证率。所以，参考文献数量较多的论文它的平均引文数量就比较大，而且参考文献越准确，读者查阅参考文献就更方便，读者能分享文献信息资源就越多。 根据我们的分析研究，提高学术期刊影响因子，应该在以下几个方面用功夫： ⒈鼓励高质量论文在我国首先发表
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中国学术期刊影响因子年报、国际引证报告发布 王保纯 2012年12月28日07:59 来源：光明日报 中国学术期刊电子杂志社、中国科学文献计量评价研究中心与清华大学图书馆26日共同发布了《中国学术期刊影响因子年报（2012版）》和《中国学术期刊国际引证报告（2012版）》，同时还首次发布了2012年度中国最具国际影响力学术期刊和中国国际影响力优秀期刊，科技界和社科界418个学术期刊分别入选两个名单。 此前，我国对于学术期刊国际影响力的评价，多以SCI（科学引文索引）、SSCI（社会科学引文索引）等国际权威检索机构收录与否作为唯一衡量标准，很多未被收录期刊往往不被看好。《中国学术期刊国际引证报告》的发布是我国学术期刊乃至学术评价领域的一个突破性进展，是我们国家，也是国际上第一次从文献计量的角度，全面、系统、深入地向社会揭示中国学术期刊走向世界取得的成果和存在的问题。此举标志着我国学术期刊有了统一的国际影响力认证标识。 中国科学文献计量评价中心主任杜文涛介绍了此次研究的有关情况。他说，中国最具国际影响力学术期刊和中国国际影响力优秀期刊，是依据《中国学术期刊国际引证报告（2012版）》，按2011年度中国学术期刊被SCI期刊、SSCI期刊引用的总被引频次和影响因子排序，经综合计算，并经40多位期刊界专家审议，最终遴选出的TOP5%期刊和TOP5%-10%期刊。在中国最具国际影响力学术期刊中，科技期刊备选3533种，由上述方法选出175种；人文社科类备选680种，选出34种，共计209种。同样，在中国国际影响力优秀期刊中，由上述方法选出科技类期刊和人文社科类期刊也分别为175种和34种，共计209种。参与报告研制的研究人员惊喜地发现，不少非SCI、SSCI收录期刊比SCI、SSCI收录期刊具有更高的被引用次数。在上榜的418个期刊中，中文期刊达312个。
四种中文核心期刊评价体系资料介 绍 对中国内地出版的期刊中核心期刊的认定，目前国内比较权威的有以下几种版本： 第一种是中国科技信息研究所（简称中信所）每年出一次的《中国科技期刊引证报告》（限理工科期刊，以下简称《引证报告》）。中信所每年第四季度面向全国大专院校和科研院所发布上一年的科研论文排名。排名包括SCI、Ei、ISTP 分别收录的论文量和中国期刊发表论文量等项指标。《引证报告》以1300多种中、外文科技类期刊作为统计源，报告的内容是对这些期刊进行多项指标的统计与分析，其中最重要的是按类进行“影响因子”排名。 第二种是北京大学图书馆与北京高校图书馆期刊工作研究会联合编辑出版的《中文核心期刊要目总览》（以下简称《要目总览》）。《要目总览》不定期出版，1996年出版了第一版，2000年出了第二版。《要目总览》收编包括社会科学和自然科学等各种学科类别的中文期刊。其中对核心期刊的认定通过五项指标综合评估。 《引证报告》统计源期刊的选取原则和《要目总览》核心期刊的认定各依据了不同的方法体系，所以二者界定的核心期刊（指科技类）不完全一致。 在《引证报告》和《要目总览》中每次都被评为核心期刊的期刊在其刊名前面加注了“#”，共597种。被《要目总览》1996年版，2000年版都定为核心期刊的社科类期刊，加注“=”，共434种。此外，被1999年EI和SCI收录的期刊，分别注以“+”(71种)或“ &”(28种)。 第三种是中国科学引文数据库(http://159.226.100.178/html/lyqkb.htm，限于理工科期刊)。它是由中国科学院文献情报中心建立的, 分为核心库和扩展库。核心库的来源期刊经过严格的评选,是各学科领域中具有权威性和代表性的核心期刊。我校在科研成果认定中把中国科学引文数据库核心库中的刊物均认定为核心期刊。 第四种是《中国人文社会科学核心期刊要览》。它是由中国社会科学院文献信息中心和社科文献计量评价中心共同建立的核心期刊库，我校在科研成果认定中均认定为核心期刊。 国内核心期刊，我院以最新版（目前以2004版）《中文核心期刊要目总览》为基础，在此基础上将核心期刊分为A、B、C、D四类。 国际国内重要检索系统简介
经济学 排名期刊名称主办单位刊号2010年2011年2012年2013年（五年）四年平均值1经济研究中国社会科学院经济研究所CN11-1081/F9.838.60911.55514.45311.112 2会计研究中国会计学会CN11-1078/F8.983 5.9097.0849.0357.753 3经济学（季刊）北京大学中国经济研究中心CN 11-6010/F—— 4.703 4.267 5.386 4.785 4金融研究中国金融学会CN11-1268/F 5.003 3.423 4.669 5.902 4.749 5中国工业经济中国社会科学院工业经济研究所CN11-3536/F 4.797 4.073 3.814 5.644 4.582 6世界经济中国社会科学院世界经济与政治研究所CN11-1138/F 4.535 3.557 3.965 5.742 4.450 7数量经济技术经济研究数量经济与技术经济研究所CN11-1087/F 3.307 3.988 4.318 4.961 4.144 8国际金融研究中国国际金融学会CN11-1132/F 5.326 3.170 3.389 3.066 3.738 9审计研究中国审计学会CN11-1024/F 3.573 2.560 3.878 4.486 3.624 10中国农村经济中国社会科学院农村发展研究所CN11-1262/F 3.341 3.018 3.417 3.782 3.390 11中国农村观察中国社会科学院农村发展研究所CN11-3586/F 2.673 2.193 2.750 4.628 3.061 12财经研究上海财经大学CN31-1012/F 3.135 2.258 2.589 3.223 2.801 13农业经济问题中国农业经济学会CN11-1323/F 2.854 2.478 2.425 3.200 2.739 14中国土地科学中国土地学会、中国土地勘测规划院CN11-2640/F 2.402 2.675 2.518 2.999 2.649 15国际经济评论中国社会科学院世界经济与政治研究所CN11-3799/F 3.753 2.385 2.285 2.143 2.642 16世界经济研究上海社会科学院世界经济研究所CN31-1048/F 3.308 2.473 2.188 2.395 2.591 17国际贸易问题对外经济贸易大学CN11-1692/F 2.905 2.477 2.242 2.690 2.579 18经济科学北京大学CN11-1564/F 3.083 1.968 2.185 3.065 2.575 19南开经济研究南开大学经济学院CN12-1028/F 2.508 1.323 2.424 3.025 2.320 20农业技术经济中国农业技术经济研究会CN11-1883/S 2.221 1.798 1.901 2.549 2.117 21世界经济文汇复旦大学CN31-1139/F 2.143 1.453 2.245 2.596 2.109 22财贸经济中国社会科学院财经战略研究院CN11-1166/F 2.059 1.533 2.240 2.560 2.098 23经济学家西南财经大学CN51-1312/F 2.08 1.593 2.347 2.303 2.081 24经济理论与经济管理中国人民大学CN11-1517/F 2.272 1.718 2.075 2.172 2.059 25证券市场导报深圳证劵交易所综合研究所CN44-1343/F 2.641 1.602 1.687 2.142 2.018 26产业经济研究南京财经大学CN32-1683/F 1.783 1.763 2.153 2.283 1.996 27经济评论武汉大学CN42-1348/F 1.944 1.673 2.013 2.113 1.936 28国际贸易中国商务出版社CN11-1600/F 2.774 2.023 1.542 1.363 1.926 29财经科学西南财经大学CN51-1104/F 2.179 1.584 1.673 1.768 1.801 30当代经济科学西安交通大学CN61-1400/F 1.944 1.447 1.675 2.093 1.790 31现代日本经济吉林大学、全国日本经济学会CN22-1065/F 1.8 1.863 1.829 1.414 1.727 32财经问题研究东北财经大学CN21-1096/F 1.965 1.317 1.567 1.933 1.696 33财经理论与实践湖南大学CN43-1057/F 2.032 1.530 1.460 1.743 1.691 34城市发展研究中国城市科学研究会CN11-3504/TU 1.448 1.569 1.822 1.896 1.684 35审计与经济研究南京审计学院CN32-1317/F 1.42 1.413 1.859 2.002 1.674 36当代财经江西财经大学CN36-1030/F 1.774 1.468 1.685 1.747 1.669 37南方经济广东经济学会、广东省社会科学院CN44-1068/F 1.773 1.181 1.589 2.094 1.659 38上海财经大学学报上海财经大学CN31-1817/C 1.88 1.380 1.658 1.687 1.651 39宏观经济研究国家发展和改革委员会宏观经济研究院CN11-3952/F 1.915 1.535 1.625 1.460 1.634 40商业经济与管理浙江工商大学CN33-1336/F 1.738 1.235 1.458 1.803 1.559 41山西财经大学学报山西财经大学CN14-1221/F 1.594 1.277 1.602 1.724 1.549 42经济与管理研究首都经济贸易大学CN11-1384/F 1.769 1.287 1.382 1.617 1.514 43上海经济研究上海社会科学院经济研究所CN31-1163/F 1.357 1.424 1.658 1.554 1.498 44经济社会体制比较世界发展战略研究部CN11-1591/F 1.501 1.174 1.561 1.649 1.471 45税务研究中国税务杂志社CN11-1011/F 1.779 1.133 1.611 1.360 1.471 46世界经济与政治论坛江苏省社会科学院世界经济研究所CN32-1544/F 1.886 1.442 1.288 1.207 1.456 47中央财经大学学报中央财经大学CN11-3846/F 1.605 1.253 1.349 1.508 1.429 48城市问题北京市社会科学院CN11-1119/C 1.677 1.273 1.218 1.484 1.413 49中南财经政法大学学报中南财经政法大学CN42-1663/F 1.336 1.160 1.517 1.628 1.410 50财贸研究安徽财经大学CN34-1093/F 1.256 1.194 1.524 1.637 1.403 51经济问题探索云南省发展和改革委员会CN53-1006/F 1.433 1.108 1.320 1.294 1.289 52国际经贸探索广东外语外贸大学CN44-1302/F 1.5820.987 1.110 1.249 1.232 53财经论丛浙江财经大学CN33-1154/F0.759 1.147 1.376 1.614 1.224 54金融经济学研究广东金融学院CN44-1696/F 1.139 1.130 1.252 1.252 1.193 55国际商务(对外经济贸易大学学报)对外经济贸易大学CN11-3645/F 1.15 1.150 1.296 1.163 1.190 56农村经济四川省农业经济学会CN51-1029/F 1.2570.981 1.220 1.269 1.182 57江西财经大学学报江西财经大学CN36-1224/F0.9310.872 1.370 1.291 1.116 58财政研究中国财政学会CN11-1077/F 1.0950.994 1.185 1.173 1.112 59现代经济探讨江苏省社会科学院CN32-1566/F 1.0120.994 1.346 1.088 1.110 60经济学动态中国社会科学院经济研究所CN11-1057/F 1.1370.914 1.126 1.197 1.094 61经济经纬河南财经政法大学CN41-1421/F 1.0860.884 1.141 1.239 1.088 62改革重庆社会科学院CN50-1012/F——0.503 1.161 1.591 1.085 63亚太经济福建社会科学院CN35-1014/F 1.4530.9160.9550.990 1.079 64经济纵横吉林省社会科学院CN22-1054/F 1.1880.963 1.107 1.044 1.076 65经济问题山西省社会科学院CN14-1058/F 1.1690.8940.995 1.068 1.032 66云南财经大学学报云南财经大学CN53-1209/F 1.2010.8010.8660.9110.945 67当代经济研究吉林财经大学CN22-1232/F0.9570.8230.9940.9260.925 68广东财经大学学报广东财经大学CN44-1446/F0.8640.8000.9110.8420.854 69河北经贸大学学报河北经贸大学CN13-1207/F0.7510.7390.7760.8640.783 70中国经济问题厦门大学经济研究所CN35-1020/F0.7190.3330.5820.8530.622 71价格理论与实践中国价格协会CN11-1010/F0.6860.5130.6900.5610.613 72中国社会经济史研究厦门大学历史研究所CN35-1023/F0.4960.3950.5290.5020.481 73政治经济学评论中国人民大学CN11-5859/D—————————— 以下为CSSCI扩展版来源期刊 排名期刊名称主办单位刊号2010年2011年2012年2013年（五年）四年平均值1金融评论中国社会科学院金融研究所CN11-5865/F—————— 1.778 1.778 2金融论坛城市金融研究所、中国城市金融学会CN11-4613/F 2.348 1.083 1.000 1.504 1.484 3上海金融上海市金融学会CN31-1160/F 1.801 1.251 1.390 1.215 1.414 4技术经济中国技术经济学会CN11-1444/F 1.138 1.135 1.219 1.264 1.189 5现代城市研究南京城市科学研究会CN32-1612/TU 1.1680.916 1.295 1.333 1.178 6税务与经济吉林财经大学CN22-1210/F 1.225 1.113 1.212 1.001 1.138 7消费经济湘潭大学、湖南商学院、湖南师范大学CN43-1022/F 1.215 1.041 1.165 1.129 1.138 8保险研究中国保险学会CN11-1632/F0.839 1.069 1.408 1.152 1.117
《中国学术期刊影响因子年报》评价指标体系 1.期刊影响力综合评价指标——期刊影响力指数（CI ） 统计某个年度内出版的某些源文献引证期刊的次数，可以在统计学意义上反映期刊在该统计年度产生的影响力。简单而常用的计量指标有期刊的总被引频次（TC ，广延量，评价对象为期刊已发表的所有文献）、影响因子（IF ，强度量，评价对象为期刊在统计年之前两年发表的文献）、即年指标（强度量，评价对象为期刊在统计年发表的文献）等。 显然，上述指标的评价对象是期刊在不同时期发表的文献，且评价角度、计量方法各不相同，任一指标都不能全面反映期刊的影响力。期刊评价中片面强调其中某个指标，都会导致期刊出现片面发展倾向，甚至引发期刊的学术不端行为，干扰期刊正常发展。因此，人们一直在希望找到一个综合反映期刊影响力的计量指标。然而，过去这方面的工作总是试图将TC 、IF 等指标先验地假设为同一线性空间的可加标量，按一组人为设定的权重参数拟合为一个“综合指标”，而未注意区分这些指标的内禀属性，得到的期刊排序结果也难以给予合理的解释。 我们在2013年首次提出了一种综合评价学术期刊影响力的方法，连续三年应用于“中国最具国际影响力学术期刊”的遴选，基本原理、计算方法和结果得到了国内外学术界和期刊界的基本认可。 1.1期刊影响力指数（CI ）的基本定义 定义1：期刊影响力排序空间 在某种可比较大小的期刊范围内（同一学科内）将TC 、IF 分别归一化处理为tc 、if ，并按其大小进行期刊排序，即可在排序意义上将TC 、IF 映射到一个2维空间，称为“期刊影响力排序空间”。 定义2：期刊影响力等位线 在“期刊影响力排序空间”内，定义影响力最大的期刊为（1,1），各刊与之的距离为 22B -1)A 1(R ） （+-=，期刊影响力相等的点连成的线即为期刊影响力等位线。显然，等位线就是以（1,1）为圆心的圆弧，见图1。 定义3：期刊影响力指数（CI ） 学术期刊影响力指数（Academic Journal Clout Index ，简称CI ），是反映一组期刊中各刊影响力大小的综合指标，它是将期刊在统计年的总被引频次（TC ）和影响因子（IF ）双指标进行组内线性归一后向量平权计算所得的数值，用于对组内期刊排序。 CI 的计算公式为： [][]1,0B T C T C T C T C B 1,0A IF IF IF IF A 1)B 1()A 1(2CI 2 2∈--= ∈--=-+--=组内最小 组内最大组内最小个刊组内最小组内最大组内最小 个刊其中）（ CI 的几何意义如下：
序号期刊名称影响因子 1 经济研究8.619 3 会计研究5.475 4 中国社会科学4.309 11 中国工业经济3.099 14 中国农村经济2.952 16 高等教育研究2.88 17 教育研究2.811 21 农业经济问题2.705 25 金融研究2.649 41 世界经济2.247 47 北京大学教育评论2.158 57 国际金融研究2.019 58 经济科学2.014 61 中国软科学1.968 80 中国高教研究1.841 89 管理世界1.713 98 国际经济评论1.675 101 中国高等教育1.66 102 南开管理评论1.659 104 教师教育研究1.638 106 中国远程教育1.633 109 教育与经济1.625 111 国际贸易问题1.619 112 经济学家1.614 117 清华大学教育研究1.574 134 世界经济研究1.497 148 经济地理1.452 149 改革1.449 154 财经研究1.433 157 管理科学学报1.411 169 课程.教材.教法1.364 172 高教探索1.355 178 教育发展研究1.338 180 外国经济与管理1.337 185 财贸经济1.322 207 中国人民大学学报1.259 210 南开经济研究1.256 217 北京师范大学学报(社会科学版) 1.241 220 农业技术经济1.233 228 求是1.215 232 经济评论1.2 244 财经科学1.174 249 比较教育研究1.166 253 国际贸易1.158 258 中南财经政法大学学报1.151 263 北京大学学报(哲学社会科 学版) 1.14 264 数量经济技术经济研究 1.139 268 经济理论与经济管理1.129 274 财经理论与实践1.108 277 经济社会体制比较1.102 279 宏观经济研究1.097 288 世界经济与政治1.077 295 金融论坛1.067 297 教育学报1.065 301 财经问题研究1.061 308 当代经济科学1.055 320 审计与经济研究1.035 323 浙江大学学报(人文社会科 学版) 1.025 324 人口与经济1.025 330 商业经济与管理1.011 335 现代大学教育1 345 中央财经大学学报0.988 350 华中师范大学学报(人文社 会科学" 0.985 353 农村经济0.982 354 经济学动态0.982 357 经济纵横0.975 363 中国经济史研究0.961 380 财经论丛0.94 381 上海经济研究0.939 417 农业经济0.906 420 财贸研究0.902 425 当代财经0.897 444 外国教育研究0.878 450 黑龙江高教研究0.873 451 江苏大学学报(自然科学版) 0.872 462 中共中央党校学报0.856 474 管理评论0.848 497 经济与管理研究0.82 504 中国教育学刊0.814 505 南京大学学报(哲学.人文科 学.社" 0.814 511 教育研究与实验0.805 523 证券市场导报0.793 531 中国职业技术教育0.787 550 世界经济与政治论坛0.771 561 北京工商大学学报(社会科 学版) 0.76 567 世界经济文汇0.755 575 经济问题探索0.748 576 财会研究0.748 580 上海金融0.746 593 教学与研究0.74 594 国际经贸探索0.74 595 中山大学学报(社会科学版) 0.739 598 清华大学学报(哲学社会科 学版) 0.737 611 经济体制改革0.728 619 消费经济0.723 623 经济问题0.721 631 教育理论与实践0.715 694 国际商务研究0.674 710 经济经纬0.662 729 国际经济合作0.651 731 教育探索0.65 778 辽宁教育研究0.622 832 中国金融0.593 887 中南民族大学学报(人文社 会科学" 0.565 949 宏观经济管理0.539 952 亚太经济0.537 1024 商业研究0.508 1061 金融理论与实践0.493 1070 南方经济0.49 1098 生态经济0.477 1123 教育评论0.469 1159 商业时代0.457 1174 财会通讯(综合版) 0.453 1191 税务与经济0.444 1192 广州化学0.444
Ranking Journal Title Impact Factor 带#者为EI亦收录者 1. Biochemical Research Methods （生物化学研究方法） 1 Current Opinion In Biotechnology 3.181 2 Journal Of Chromatography A 2.697 3 Bioconjugate Chemistry 2.440 4 Methods In Enzymology 2.435 5 Applied Immunohistochemistry 2.162 6 Cytometry 2.150 7 Acta Crystallographica Section D-Biological Crystallography 2.118 8 Chromatographia 2.079 9 Journal Of Immunological Methods 2.043 10 Analytical Biochemistry 2.017 #11 Journal Of Molecular Graphics & Modelling 2.012 12 Biotechniques 1.913 13 Journal Of Chromatographic Science 1.696 14 Journal Of Virological Methods 1.623 15 Journal Of Chromatography B 1.588 16 Transgenic Research 1.430 17 Protein Expression And Purification 1.341 18 Journal Of Neuroscience Methods 1.335 #19 Journal Of Liquid Chromatography & Related Technologies 1.272 20 Biomedical Chromatography 1.171 21 Molecular And Cellular Probes 1.110 22 Journal Of Microbiological Methods 0.958 23 Journal Of Labelled Compounds & Radiopharmaceuticals 0.767 24 Genetic Analysis-Biomolecular Engineering 0.696 25 Journal Of Biochemical And Biophysical Methods 0.648 26 Biologicals 0.598 27 Preparative Biochemistry & Biotechnology 0.472 28 Hybridoma 0.458 29 Journal Of Magnetic Resonance 0.000 2. Biochemistry & Molecular Biology（生物化学与分子生物学） 1 Annual Review Of Biochemistry 40.782