PENGUKURAN NILAI BULLWHIP EFFECT PADA ELEMEN ESELON SUPPLY CHAIN YANG DIPENGARUHI PERMINTAAN DAN PENJUALAN FLUKTUATIF DENGAN SIMULASI ARENA

Abstrak : Bullwhip Effect atau disebut juga Whiplash Effect adalah suatu fenomena amatan di dalam saluran distribusi yang terpicu peramalan permintaan. Semakin besar nilai bullwhip effect yang terjadi di elemen eselon supply chain menunjukan bahwa variabilitas permintaan meningkat. Selain elemen eselon supply chain distribusi waktu proses juga berpengaruh terhadap naiknya nilai bullwhip effect hal ini terjadi pada Distribusi weibull yang mempunyai rata-rata sebesar 7.09. Semakin kecil nilai bullwhip effect yang terjadi di elemen eselon supply chain menunjukan bahwa terjadi penghalusan pola pesanan pada variabilitas permintaan dari arah hilir menuju arah hulu supply chain. Kata kunci : supply chain, bullwhip effect, persediaan, variabilitas

The IDENTIFY study: the investigation and detection of urological neoplasia in patients referred with suspected urinary tract cancer - a multicentre observational study

Objective To evaluate the contemporary prevalence of urinary tract cancer (bladder cancer, upper tract urothelial cancer [UTUC] and renal cancer) in patients referred to secondary care with haematuria, adjusted for established patient risk markers and geographical variation. Patients and Methods This was an international multicentre prospective observational study. We included patients aged ≥16 years, referred to secondary care with suspected urinary tract cancer. Patients with a known or previous urological malignancy were excluded. We estimated the prevalence of bladder cancer, UTUC, renal cancer and prostate cancer; stratified by age, type of haematuria, sex, and smoking. We used a multivariable mixed-effects logistic regression to adjust cancer prevalence for age, type of haematuria, sex, smoking, hospitals, and countries. Results Of the 11 059 patients assessed for eligibility, 10 896 were included from 110 hospitals across 26 countries. The overall adjusted cancer prevalence (n = 2257) was 28.2% (95% confidence interval [CI] 22.3–34.1), bladder cancer (n = 1951) 24.7% (95% CI 19.1–30.2), UTUC (n = 128) 1.14% (95% CI 0.77–1.52), renal cancer (n = 107) 1.05% (95% CI 0.80–1.29), and prostate cancer (n = 124) 1.75% (95% CI 1.32–2.18). The odds ratios for patient risk markers in the model for all cancers were: age 1.04 (95% CI 1.03–1.05; P < 0.001), visible haematuria 3.47 (95% CI 2.90–4.15; P < 0.001), male sex 1.30 (95% CI 1.14–1.50; P < 0.001), and smoking 2.70 (95% CI 2.30–3.18; P < 0.001). Conclusions A better understanding of cancer prevalence across an international population is required to inform clinical guidelines. We are the first to report urinary tract cancer prevalence across an international population in patients referred to secondary care, adjusted for patient risk markers and geographical variation. Bladder cancer was the most prevalent disease. Visible haematuria was the strongest predictor for urinary tract cancer

A strategy to ensure the correct thickness of optical couplers in concentrating photovoltaic systems

Adding a dielectric Secondary Optical Element (SOE) to a Concentrating Photovoltaic (CPV) system provides several advantages. Besides increasing the concentration-acceptance angle product attainable by the system, a more uniform irradiance on the solar cell can also be achieved. The most common solution to glue the SOE and the solar cell consists in using an elastomer such as silicone. In this case, the silicone is acting both as an optical coupler to reduce Fresnel losses and as a mechanical bond. In this paper, we present a new approach to fix the thickness of the silicone in order to ensure a good adherence

Outdoor Performance of PV Technologies in Simulated Automotive Environments

GaAs, monocrystalline Si, and multicrystalline Si modules were tested in a configuration designed to simulate car-roof-integrated mounting. The increase in module temperature above ambient was similar for the four Si modules, but less (~76%) for the GaAs modules. Local temperatures within each module were strongly dependent on the optical properties of the back sheet. The lower operating temperature combined with smaller temperature coefficient of the GaAs modules resulted in higher performance ratios for the GaAs modules even for ambient temperature <; 25°C. The quantification of the relative performance of the modules in a thermal environment relevant to implementation in vehicles provides information for the selection of PV modules for this emerging application

Experimental characterization of achromatic doublet on glass (ADG) Fresnel lenses

In this paper we present a comprehensive experimental characterization of Achromatic Doublet on Glass (ADG) Fresnel lenses. When compared to a Silicone on Glass (SoG) Fresnel lens, the ADG Fresnel lens shows higher tolerance to displacements of the lens with respect to the optimal lens-to-cell distance. Furthermore, lower sensitivity of the ADG Fresnel lens to temperature variations has been experimentally proven

Impact of the temperature dependence of CPV optics transmittance on the current mismatch of multi-junction solar cells

The influence of spectra and temperature dependence of concentrator photovoltaics (CPV) optics is investigated by modelling yearly series of ambient conditions, such as typical meteorological year (TMY) data, and simulating the response of relevant CPV technologies. Results show the influence the optics have on the effective spectra available at the solar cell level. This allows us to find the limiting factors of a CPV module performance and permits energy yield predictions

Spectrally-resolved optical efficiency using a multi-junction cell as light sensor: Application cases

The experimental method to determine the spectrally-resolved optical efficiency of concentrating optics is described in this paper. The measurement uses a multi-junction solar cell as light sensor and a series of band-pass filters to isolate the optical performance of different narrow spectral bands throughout the spectrum of interest. Additional bias light is provided to saturate the subcells whose spectral response is out of the transmittance of every band-pass filter. The method allows the characterization of the combined transmittance, reflectance and absorbance of every material composing the optics including optical couplers and thin layers such as antireflective coatings. The two application cases included illustrate the potential of this novel characterization technique. Firstly, a novel refractive concentrator, the Achromatic Doublet on Glass (ADG) Fresnel lens is measured. Secondly, the method is applied to analyze the degradation of outdoor exposed glass molded Secondary Optical Elements (SOE

Design Strategy for Low-Power Consumption in Solar Trackers

The new energy generation technologies that transform the solar energy, require a high accuracy for the tracking of the solar vector path, which increases the system energy consumption and reduces the entire system performance. From an optimization approach, a novel design strategy for low-power trackers is proposed, which consists of two main stages, a first for the physical tracker design optimization, and a second for the design of the tracker behavior. For the validation of the proposed design strategy, the implementation is presented through the development of a solar tracker prototype. For the implementation of the second stage, three Tracking Error Minimization Strategies (TEMS) are proposed (PI, GPI, and cascade control), and four Energy Saving Strategies (ESS) are proposed. The presented experimental results show that the saving energy strategy can reduce the energy consumption in up to 27.2771% in tracking tasks with an absolute maximum tracking error of 0.08°, and obtaining a low-power prototype tracker with 5.4749 Wh energy consumption. The proposed design strategy allows the design of solar trackers with a balance between the energy consumption and the tracking error

Indoor experimental assessment of the efficiency and irradiance spot of the achromatic doublet on glass (ADG) fresnel lens for concentrating photovoltaics

We present a method to characterize achromatic Fresnel lenses for photovoltaic applications. The achromatic doublet on glass (ADG) Fresnel lens is composed of two materials, a plastic and an elastomer, whose dispersion characteristics (refractive index variation with wavelength) are different. We first designed the lens geometry and then used ray-tracing simulation, based on the Monte Carlo method, to analyze its performance from the point of view of both optical efficiency and the maximum attainable concentration. Afterwards, ADG Fresnel lens prototypes were manufactured using a simple and reliable method. It consists of a prior injection of plastic parts and a consecutive lamination, together with the elastomer and a glass substrate to fabricate the parquet of ADG Fresnel lenses. The accuracy of the manufactured lens profile is examined using an optical microscope while its optical performance is evaluated using a solar simulator for concentrator photovoltaic systems. The simulator is composed of a xenon flash lamp whose emitted light is reflected by a parabolic mirror. The collimated light has a spectral distribution and an angular aperture similar to the real Sun. We were able to assess the optical performance of the ADG Fresnel lenses by taking photographs of the irradiance spot cast by the lens using a charge-coupled device (CCD) camera and measuring the photocurrent generated by several types of multi junction (MJ) solar cells, which have been previously characterized at a solar simulator for concentrator solar cells. These measurements have demonstrated the achromatic behavior of ADG Fresnel lenses and, as a consequence, the suitability of the modelling and manufacturing methods

Technical Specification IEC TS 62989:2018 : Primary Optics for Concentrator Photovoltaic Systems

The first edition of the Technical Specification (TS) on Primary Optics for Concentrator Photovoltaic (CPV) Systems, IEC TS 62989:2018, has been published by the International Electrotechnical Commission (IEC), on March 8th, 2018. TS 62989 covers aspects related to the primary optics including: product identification, optical characteristics, mechanical characteristics, materials, (design) geometry, and visual appearance. This paper focuses on the key aspects of the norm, including optical performance, in order to promote the awareness and use of the standard. We describe the three methods intended to measure the key optical characteristics of the primary elements, i.e. focal spot size and optical efficiency, by using the encircled energy. The three methods are using different light sources, optical components and receiver sensors, but yielded very similar results in a round robin test. This justifies the continued use of all three methods. The use of a website (opticstests.pbworks.com) for documentation of discussions and references was novel to the standard development. The website proved to be useful for the introduction of new members of the group. The website helped to keep track of changes to the document as well as the required actions of the project team