Oblique Transmission Research Articles

Modeling and oblique transmission characteristics of an underwater wireless optical communication channel based on ocean depth layering.

Underwater wireless optical communication is widely considered in the field of underwater communication due to its high bandwidth and low latency. In a real transmission link, the temperature and salinity of seawater, chlorophyll concentration, and bubble density vary with ocean depth. Therefore, the depth of the optical transmitter in seawater and the tilt angle of the beam will exhibit different beam transmission characteristics. In this paper, an underwater oblique-range layered channel model considering the combined effects of dynamic turbulence, absorption, and scattering is developed based on real data of seawater at different depths measured by the Global Ocean Observing Buoy Argo and the Woods Hole Oceanographic Institution BCO-DMO. The effects of transmission distance, transmitter tilt angle, and transmitter depth on the oblique-range transmission characteristics of the beam in seawater are discussed. The simulation results show that, at the same transmission distance, the beam centroid displacement increases with an increase in transmitter depth only when the transmitter is located above the interior of the thermocline. When the transmitter is located below the interior of the thermocline, the influence of the transmitter tilt angle on the beam centroid displacement decreases. This indicates that at different depths within the interior of the thermocline, the optical beam transmission characteristics exhibit significant variations.

A basic study on laboratory measurement of oblique-incidence sound transmission loss of building elements

Understanding the sound insulation performance of building elements under oblique incidence conditions is occasionally required for assessing the indoor sound environment of high-rise buildings that face roads or railways. In order to gain knowledge toward establishing a laboratory measurement method for oblique incident sound transmission loss, a measurement system was set up in a coupled reverberation room and anechoic chamber with a movable sound source. For verification of the system, a pilot measurement was carried out with a large glass pane, while the experimental set-up was also numerically simulated by FEM. In the experimental results, transmission loss was observed to depend on incidence angle in correlation with the coincidence effect, roughly obeying theory. However, it was found that the incident power estimated from the surface sound pressure on the specimen differs somewhat from that estimated using loudspeaker directivity in a free field. This discrepancy is thought due to edge diffraction from the beading around the glass pane, and this was confirmed by the numerical results. Further, this edge diffraction may also have caused the observed coincidence effect under normal incidence.

Oblique laser transmission and scattering characteristics of multilayer ice-water mixed clouds based on the successive scattering method

Clouds are widely distributed in the atmosphere, which is an important factor affecting the laser engineering application. In the paper, we developed a scattering transmission model of laser light in multilayer ice-water mixed clouds for applications in laser communication, laser detection, and laser weapons. Based on the successive scattering method, the direct transmission and first-order scattering of the laser between an aircraft and a target are numerically calculated in different cloud structures. The effects of the vertical structure of the clouds and the position of the aircraft and the target on the laser scattering are analyzed. The results show that the direct transmission can always have minimal and maximal values at the bottom and top of the clouds, respectively, while the peak of the first-order scattering appears near the top of the clouds. Compared to ice clouds, water clouds will produce a huge attenuation of the laser transmission. Our results can provide theoretical guidance for engineering applications in the real cloud environment.

Between flowers, humans, and honeybees: Local ecological knowledge associated with apiculture in two areas of Silípica department, Santiago del Estero, Argentina

The production of honey for consumption is one of humans’ most intriguing activities in biocultural terms. Studies on Local Ecological Knowledge linked to Apiculture with Apis mellifera (LEKHA) are limited, particularly in Santiago del Estero (northern Argentina). In this work, we compared the LEKHA of beekeeping families in two different landscapes that show distinct socio-ecological characteristics: “rainfed” and “irrigation.” Through semi-structured and free interviews and the construction of local calendars, together with 85% of the beekeepers of these zones, we investigated the LEKHA, honeybee flora and methods of acquisition and transmission of management knowledge and practices. Participants mentioned 96 honeybee flora species (63 in rainfed and 71 in irrigation), mainly native species, which provide with nectar and pollen. The apicultural and floral calendar was similar in these two areas, although the areas differed in the time of year certain activities were carried out and the richness and abundance of plant strata. This similarity could be related mainly to the strong cultural attachment of inhabitants to some elements of their native “Monte” landscape which, despite having undergone some anthropic modifications, remains functional for beekeeping. The LEKHA in both areas was learned idiosyncratically and by oblique transmission. We show how an activity related to the environment recreates and stimulates environmental knowledge, such that flowers, honeybees, and people form a bond of mutual care.

Schrödinger Operators with Oblique Transmission Conditions in {mathbb R}^2

In this paper we study the spectrum of self-adjoint Schrödinger operators in L^2(mathbb {R}^2) with a new type of transmission conditions along a smooth closed curve Sigma subseteq mathbb {R}^2. Although these oblique transmission conditions are formally similar to delta '-conditions on Sigma (instead of the normal derivative here the Wirtinger derivative is used) the spectral properties are significantly different: it turns out that for attractive interaction strengths the discrete spectrum is always unbounded from below. Besides this unexpected spectral effect we also identify the essential spectrum, and we prove a Krein-type resolvent formula and a Birman-Schwinger principle. Furthermore, we show that these Schrödinger operators with oblique transmission conditions arise naturally as non-relativistic limits of Dirac operators with electrostatic and Lorentz scalar delta -interactions justifying their usage as models in quantum mechanics.

Will Indigenous Ecological Knowledge Vanish? Assessing Persistence of the Celako kemali in Farming Practices among the Serawainese in Bengkulu, Indonesia

Indonesia is home to many indigenous peoples who can preserve the environment through their traditions amid the increasing of external values ​​and lifestyles’ penetration. The following presents the indigenous ecological knowledge of the Serawai people in the form of the celako kemali. Based on insights from the Indigenous research methods, this study aims first to assess the persistence of the celako kemali as a method for farming practices. Second, to identify transmission patterns of the celako kemali among generations in the Serawai community. This study found that there were 19 types of celako kemali. The current analysis demonstrates that, out of the 19 celako kemali, three types have been completely abandoned, five are still in use but with minor modifications, and eleven are still valid by established standards. The first generation acquires knowledge from their parents through the internalization process within the family. This first generation still preserves and maintains the 19 celako kemali daily farming activities. The second generation acquires knowledge through internalization within the family and horizontally by sharing experiences with other farmers, but horizontal channels are more dominant. This generation knows the 19 types of the celako kemali, although they dare to modify five types without losing the essence of their body of knowledge. The third generation acquires knowledge through vertical and oblique transmission, in which the oblique channel is predominant. This third generation learns a lot from village elders unrelated to the family, teachers, and mass media. However, this generation has abandoned completely three types of the celako kemali.

The vortex cosine-gaussian beam in strongly nonlocal nonlinear media

Different cosine phase factors n can make the vortex cosine-Gaussian beam(VCGB) exhibit a multi-ring structure. When the number of vortex points of the VCGB was 1, the analytical expression of the orbital angular momentum was the Dawson integral function. By the split-step Fourier method, the propagation of a VCGB in nonlocalized medium was numerically simulated. It was found that when the vortex point was asymmetric with respect to the origin, the energy flow distribution of the VCGB was asymmetric. The center of mass is move with the transmission of the beam in nonlocal medium, resulting in oblique transmission. If the sign in front of the imaginary part of the vortex point changes, the rotation direction of the soliton changes. When two VCGBs were transmitted in nonlocalized medium, they can be intertwined or transmitted in serpentine shapes. Therefore, the beam information can be encoded by changing the phase factor and the number of vortex points. The beam transmission path in the nonlocal medium can be controlled by changing the vortex position.

Cultural Learning Among Pastoralist Children

Cultural learning is a key feature of culture and our humanity. Although studies exist on children’s learning in subsistence farmers and hunter-gatherers, comparable cross-cultural studies have not been conducted for pastoralists. The purpose of this paper is to identify and describe patterns of cultural learning in pastoralists and to compare these patterns to what we know about cultural learning in hunter-gatherers. The study utilizes 13 cultures coded as pastoralists in eHRAF World Cultures. The search located 198 texts in ethnographies with precise information on how pastoral children learn. Overall, we found that children acquired most pastoral skills and knowledge in early childhood, children were most likely to learn from parents (vertical transmission) and non-parental adults (oblique transmission), a relationship between age and specific modes of transmission did not exist, various forms of teaching were the most frequently mentioned processes of learning, and the frequency of teaching did not vary by the child’s age. When hunter-gatherer’s and pastoralist’s patterns of cultural learning were compared several similarities emerged: most accounts of learning occurred in early childhood, children were most likely to learn from parents and non-parental adults, and various forms of teaching were the most frequently mentioned processes of learning. Several differences in cultural learning between the two groups were identified: pastoralist ethnographers were less likely than hunter-gatherer ethnographers to mention learning from peers and more likely to mention learning via local enhancement and stimulus enhancement.

On the evolutionary language game in structured and adaptive populations.

We propose an evolutionary model for the emergence of shared linguistic convention in a population of agents whose social structure is modelled by complex networks. Through agent-based simulations, we show a process of convergence towards a common language, and explore how the topology of the underlying networks affects its dynamics. We find that small-world effects act to speed up convergence, but observe no effect of topology on the communicative efficiency of common languages. We further explore differences in agent learning, discriminating between scenarios in which new agents learn from their parents (vertical transmission) versus scenarios in which they learn from their neighbors (oblique transmission), finding that vertical transmission results in faster convergence and generally higher communicability. Optimal languages can be formed when parental learning is dominant, but a small amount of neighbor learning is included. As a last point, we illustrate an exclusion effect leading to core-periphery networks in an adaptive networks setting when agents attempt to reconnect towards better communicators in the population.

Infrared multiple‐angle incidence resolution spectrometry for vapor‐deposited amorphous water

AbstractInfrared multiple‐angle incidence resolution spectrometry (IR‐MAIRS) is a recently developed spectroscopic technique that combines oblique incidence transmission measurements and chemometrics (multivariate analysis) to obtain both pure in‐plane (IP) and out‐of‐plane (OP) vibration spectra for a thin sample. IR‐MAIRS is established for analyzing the molecular orientation of organic thin films at atmospheric pressure, but it should also be powerful for the structural characterization of vapor‐deposited thin samples prepared in a vacuum. The application of IR‐MAIRS to vapor‐deposited amorphous water is particularly interesting in the fields of physical and interstellar chemistry, because it is a representative model material for interstellar icy dust grains. We recently developed an experimental setup for in situ IR‐MAIRS under low‐temperature, ultrahigh‐vacuum conditions, which thus facilitates measurements of interstellar ice analogs such as vapor‐deposited amorphous water. This review considers the theoretical framework of IR‐MAIRS and our recent experimental results for vapor‐deposited amorphous water. We present spectroscopic signatures for the perpendicular orientation of dangling‐OH bonds for three‐coordinated water molecules at the surface of amorphous water at 90 K. The absolute absorption cross section of the three‐coordinated dangling‐OH bonds is quantitatively measured as 1.0 ± 0.2 × 10−18 cm2 at 3696 cm−1. As IR‐MAIRS can essentially be conducted using only a Fourier‐transform IR spectrometer and an angle‐controllable linear polarizer, it is a useful, low‐cost, and simple spectroscopic technique for studying laboratory analogs of interstellar ices including vapor‐deposited amorphous water.

Laminated plate-type acoustic metamaterials with Willis coupling effects for broadband low-frequency sound insulation

Acoustic metamaterials provide a powerful tool for designing effective noise-reducing means at subwavelength scales. This paper is concerned with the sound insulation characteristics of plate-type acoustic metamaterials under some pragmatic conditions, including the effect of structure scale on the sound insulation performance, the Willis coupling effect in multilayer plate-type acoustic metamaterials, and the acoustic coupling between plate-type acoustic metamaterials and existing structures. Herein, laminated plate-type acoustic metamaterials (LPAM) composed of multilayer plate-type acoustic metamaterials sandwiched with porous materials are constructed to effectively insulate broadband low-frequency noise. By a numerical study on the normal, oblique, and diffuse-field incident sound transmission loss (STL) of the proposed LPAM and its constituent layers, the presence of superior sound insulation performance and the governing physical mechanism are discussed. The effectiveness of numerical study is validated by the STL experiments performed in a sound impedance tube for small-scale samples and in a reverberation and anechoic chamber for large-scale samples. The proposed LPAM construction, analysis technique, and reported findings may contribute to the design and application of plate-type acoustic metamaterials for broadband low-frequency noise control.

Iron Age craftworks in the southeast of the Iberian Peninsula. An approach based in Cultural Inheritance Theory

The aim of this paper is to examine the craftwork on hard materials of animal origin from the Iron Age of the southeast of the Iberian Peninsula. We deal with the processes of craftsmanship, transmission of knowledge and the circulation of ivory combs and perforated bone plates. The Cultural Inheritance Theory offers a framework to help identify social dynamics in the craft productions and the transmission of the cultural knowledge between and among individuals (vertical, horizontal or oblique). Therefore, the consequences of these cultural transmission processes will be different for each artefact. This could be used to investigate relative levels of standardization within and between groups. For this we use various morphometric measurements related to the technological process of making combs and perforated plates. The results point to an oblique transmission with particularities linked to each object related to their formal and decorative characteristics and owing to their raw materials.

Islamic boarding schools and human rights enforcement transmission of cultural values for disabilities

The inclusive boarding school model is not only a form of embodiment of education that respects diversity and eliminates discrimination. However, it is more critical as a form of application, essence, and religion, the theological substance that teaches the equality of human rights, tolerance, and respect for others in all aspects of life. This research was conducted to know the inclusive boarding school education model initiated by the founder of An-nur Islamic boarding school, Tengku Drs H. Zainal Abidin. The research method used in this study is a type of qualitative research. Data collection techniques using participant observation, namely by way of researchers mingling with the object of research. The research was conducted at the An-nur Islamic Boarding School, Tingkem Asli Village, Bukit District, Bener Meriah Regency, Aceh. The research was conducted from July 2020 to July 2021. The results of this study are that the pesantren model initiated by the founder is an integrated, inclusive boarding school that was officially established in 2010. Inclusive Integration is a pesantren education model that unites regular (typical) students with ABK students (Children with Special Needs) in one Islamic boarding school environment. with an integrated education model, namely the Integration between the concepts of Islamic boarding school education and entrepreneurship with a learning approach that emphasizes emotional and familial. Through this model, Pesantren An-Nur can transmit cultural values for persons with disabilities through the process of enculturation, socialization, acculturation with a Chinatown style building. Cultural transmission is applied to disability in inclusive boarding schools through vertical transmission, oblique transmission, and horizontal transmission. These three cultural transmissions are carried out in the educational process at Islamic boarding schools for 24 hours through theological understanding and translating at the practical level in the form of self-accustoming, exemplary, formal and informal learning, and life skills activities for students in Islamic boarding schools.

Conformity and content-biased cultural transmission in the evolution of altruism

The evolution of altruism has been extensively modeled under the assumption of genetic transmission, whereas the dynamics under cultural transmission are less well understood. Previous research has shown that cultural transmission can facilitate the evolution of altruism by increasing (1) the probability of adopting the altruistic phenotype, and (2) assortment between altruists. We incorporate vertical and oblique transmission, which can be conformist or anti-conformist, into models of parental care, sibling altruism, and altruism between individuals that meet assortatively. If oblique transmission is conformist, it becomes easier for altruism to invade a population of non-altruists as the probability of vertical transmission increases. If oblique transmission is anti-conformist, decreasing vertical transmission facilitates invasion by altruism in the assortative meeting model, whereas in other models, there is a trade-off: greater vertical transmission produces greater assortment among genetically related altruists, but lowers the probability of adopting altruism via anti-conformity. Compared to conditions for invasion under genetic transmission, e.g., Hamilton’s rule, we show that invasion can be easier with sufficiently strong anti-conformity, and in some models, with sufficiently high assortment even if oblique transmission is conformist. We also explore invasion by an allele A that increases individuals’ content bias for altruism, in the absence of other forms of cultural transmission. If costs and benefits combine additively, A invades under previously known conditions. If costs and benefits combine multiplicatively, invasion by A and by altruism become more difficult than in the corresponding additive models.

A study on health care monitoring of femoral shaft fracture healing by using implanted antenna for wireless in-to-out body channel communication

This work proposes a health care monitoring method of femoral fractured bone healing as a novel application, based on the oblique incidence case and transmission of electromagnetic waves. The difference between the transmitted average power densities of normal and fractured bone cases is used to monitor the bone healing status. The study demonstrates the in-to-out body channel characteristics regarding the electromagnetic wave propagation and angle of incidence on a multi-layered human tissue in the range of frequencies from 100 MHz to 10 GHz. The monitoring method is presented by the analysis of electromagnetic wave propagation through a multilayer model and simulated by the CST Microwave studio. Fully insulated planar and meander half-wave dipole antennas are designed and used to simulate both types of bone fracture healing. Results show good monitoring of common types of fractures. Verification is carried out by experimental measurements on non-living animal tissues.

Conjugate distribution laws in cultural evolution via statistical learning.

Many cultural traits characterizing intelligent behaviors are now thought to be transmitted through statistical learning, motivating us to study its effects on cultural evolution. We conduct a large-scale music data analysis and observe that various statistical parameters of musical products approximately follow the beta distribution and other conjugate distributions. We construct a simple model of cultural evolution incorporating statistical learning and analytically show that conjugate distributions emerge at equilibrium in the presence of oblique transmission. The results demonstrate that the distribution of a cultural trait within a population depends on the individual's model for cultural production (the conjugate distribution law), and reveal interesting possibilities for theoretical and experimental studies on cultural evolution and social learning.

Front propagation and cultural transmission. Theory and application to Neolithic transitions

• Invasion of a population that incorporates individuals of a pre-existing population. • First model of oblique transmission (acculturation by older individuals). • Oblique transmission is the most powerful mechanism (fastest fronts). • Example of a Neolithic front can be only explained by oblique transmission. • We obtain bounds on the intensity of cultural transmission. We study the front propagation of a population that incorporates individuals of a second, pre-existing population. Previous models of such incorporation deal only with vertical cultural transmission (interbreeding) and horizontal cultural transmission (acculturation of individuals of the second population by members of the first one and of similar age). Here we present the first model of oblique transmission (acculturation by individuals of an older generation), which is more complicated because a model with age structure is necessary. We compare the new, age-structured model for oblique, horizontal and vertical transmission. The most powerful mechanism (fastest fronts) is oblique transmission. Two illustrative applications of Neolithic front propagation are presented. In one of them, the front was so fast that neither horizontal nor vertical transmission can explain it (but oblique transmission can). In the cases for which cultural transmission is a viable explanation, the observed front speed yields bounds on the intensity of cultural transmission. Our models are also of interest in many other Neolithic and non-Neolithic human range expansions, including major human migrations. Additionally, in future work the new age-structured models reported in this paper could be applied to model genetic gradients and, possibly, to similar phenomena in other species in which cultural transmission is well-known to occur.

Plate-type acoustic metamaterials with strip masses.

Plate-type acoustic metamaterials (PAM) consist of a thin plate with periodically added masses. Similar to membrane-type acoustic metamaterials, PAM exhibit anti-resonances at low frequencies at which the transmission loss can be much higher than the mass-law without requiring a pretension. Most PAM designs previously investigated in literature require the addition of up to thousands of masses per square meter. This makes manufacturing of such PAM prohibitively expensive for most applications. In this contribution, a much simpler PAM design with strip masses is investigated. An analytical model is derived which can be used to estimate the modal properties, effective mass, and oblique incidence sound transmission loss of PAM with strip masses. For high strip masses (compared to the baseplate), this analytical model can be simplified to yield explicit expressions to directly calculate the resonance and anti-resonance frequencies of such PAM. The analytical model is verified using numerical simulations and laboratory measurement results are presented to demonstrate the performance of PAM with strip masses under diffuse field excitation and finite sample size conditions.

Non-vertical cultural transmission, assortment and the evolution of cooperation.

Cultural evolution of cooperation under vertical and non-vertical cultural transmission is studied, and conditions are found for fixation and coexistence of cooperation and defection. The evolution of cooperation is facilitated by its horizontal transmission and by an association between social interactions and horizontal transmission. The effect of oblique transmission depends on the horizontal transmission bias. Stable polymorphism of cooperation and defection can occur, and when it does, reduced association between social interactions and horizontal transmission evolves, which leads to a decreased frequency of cooperation and lower population mean fitness. The deterministic conditions are compared to outcomes of stochastic simulations of structured populations. Parallels are drawn with Hamilton’s rule incorporating relatedness and assortment.

The Life History of Learning Subsistence Skills among Hadza and BaYaka Foragers from Tanzania and the Republic of Congo

Aspects of human life history and cognition, such as our long childhoods and extensive use of teaching, theoretically evolved to facilitate the acquisition of complex tasks. The present paper empirically examines the relationship between subsistence task difficulty and age of acquisition, rates of teaching, and rates of oblique transmission among Hadza and BaYaka foragers from Tanzania and the Republic of Congo. We further examine cross-cultural variation in how and from whom learning occurred. Learning patterns and community perceptions of task difficulty were assessed through interviews. We found no relationship between task difficulty, age of acquisition, and oblique transmission, and a weak but positive relationship between task difficulty and rates of teaching. While same-sex transmission was normative in both societies, tasks ranked as more difficult were more likely to be transmitted by men among the BaYaka, but not among the Hadza, potentially reflecting cross-cultural differences in the sexual division of subsistence and teaching labor. Further, the BaYaka were more likely to report learning via teaching, and less likely to report learning via observation, than the Hadza, possibly owing to differences in socialization practices.